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Breton wrote:


Not just the Nids. The purpose of the stories are one of two:

Selling the newest Whatchamacallit

Generating Tension and hype while maintaining the Status Quo.

What was the biggest story from the past couple years? The fall of Cadia. What's changed? Not much. A little fluff here and there to make the summer campaign books less forced. No more What? How did Chaos get here?!?! Same reason Hive Fleet Leviathan is attacking from Below The Galactic Plane, Necron Worlds are scattered and unknown, and I'm sure the Tau will get some sort of finger waggle soon too.

There is also a problem of narrative focus.

I mean, remember Gryphonne IV? it is ridiculous no one has even written even a short story about its destruction by Hive Fleet Leviathan. It once used to be one of the biggest Forge Worlds around yet we have a handful of paragraphs at best about its destruction.

Kind of tempted to have another crack at this topic. Not sure I asked the question I was aiming for.

No shade to the contributors, who’ve all been solid. Shade on me because “who/how to conquer Terra” is a much more interesting premise.


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As for the Tarot?

The Fool Inversed could be the Ethereal Caste finally getting a grip on unreality. Accepting that powerful, near god like beings do exist, and that there’s genuine merit to like of Farsight.

 Tyran wrote:

Breton wrote:


Not just the Nids. The purpose of the stories are one of two:

Selling the newest Whatchamacallit

Generating Tension and hype while maintaining the Status Quo.

What was the biggest story from the past couple years? The fall of Cadia. What's changed? Not much. A little fluff here and there to make the summer campaign books less forced. No more What? How did Chaos get here?!?! Same reason Hive Fleet Leviathan is attacking from Below The Galactic Plane, Necron Worlds are scattered and unknown, and I'm sure the Tau will get some sort of finger waggle soon too.

There is also a problem of narrative focus.

I mean, remember Gryphonne IV? it is ridiculous no one has even written even a short story about its destruction by Hive Fleet Leviathan. It once used to be one of the biggest Forge Worlds around yet we have a handful of paragraphs at best about its destruction.

I have always though the fall of Gryphonne IV was ripe material for a book or campaign book. As one of the most heavily fortified worlds in the southern galaxy, with a famous Titan Legion and storied history going back to the Heresy and beyond, its loss should have had more written about it.

It could easily be a story of hubris. Legio Gryphonicus's Adeptus Titanicus trait of "Lust for Glory" if kept up in the years since 30K would have made them less suited against the Tyranids. In short, the trait was the Princeps wanting glory so they would pick a particular target and pledge themselves to bringing it down for their own personal glory and honor. This works for single combat duels but I could see them getting so focused on bringing down a big Tyranid Titan they neglect the smaller creatures and get swarmed under. In fact, if the Hive Mind is aware of this trait it might even have deliberately used such tactics against the Titan Legion: have big durable Bio-Titans to hold a War Griffon Titan's attention and lure them into a trap.

It would then actually be a test of personality and willpower for a Princeps to deliberately choose to retreat from the world after it became clear it was lost rather than try to keep going and die in a blaze of glory. Sounds like a good idea for a novel.

Commissar von Toussaint wrote:

Breton wrote:
Not just the Nids. The purpose of the stories are one of two:

Selling the newest Whatchamacallit

Generating Tension and hype while maintaining the Status Quo.

Yeah, the only thing stronger than the Hive Fleet is GW's plot armor against it.

I mean the notion that they've devoured two whole galaxies just shows GW doesn't understand scale. It's the usual "No, THIS is the worst thing ever!" hype.

"Oh yeah, but did those galaxies have the holy power of the Emperor?! I think not."

It's like the other thread - the Imperium is falling and always will be.

I think you missed my first sentence and the last one. Its not just the Nids and While Maintaining the Status Quo. Cadia fell, what changed? Not much. The only big changes are to make the status quo standoff more immersive.


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 Mad Doc Grotsnik wrote:
Kind of tempted to have another crack at this topic. Not sure I asked the question I was aiming for.

What was the question you were aiming for? If you're looking for a Who/How each is different. Almost all factions have some sort of claim/plan/theme for it. Tau will gobble up Imperium Worlds until they can subvert Terra itself For The Greater Good. Dark Eldar will break through the Emperor's Webway Gate or whatever it was he was working on. GSC will start in the bowels of the world and work their way up, probably having the easiest start and the toughest finish. Orks have the most likely laziest path in The Biggest Zerg You've Ever Seen sacrificing entire space hulks just to get some through the landing. The Imperium Forces obviously don't have to, and don't have a plan. Aeldari are most likely uninterested but share the Webway. Not the biggest stretch to make Terra a Tomb World so the Necrons are already there and just haven't woken up Tutankenhamen The First King yet.

Breton wrote:
I think you missed my first sentence and the last one. Its not just the Nids and While Maintaining the Status Quo. Cadia fell, what changed? Not much. The only big changes are to make the status quo standoff more immersive.

No, I saw it but had no idea what happened because I'm not that up on the lore these days. Best not to quote something you know nothing about.

Which makes our point: if you completely ignore GW plot advancement it's fine because none of it has any practical effect.

That gets us back to the OP's question, and my counter of "why bother?" Barring some Mary Sue plot twist, there's a reason why Terra endures. Before talking about taking it, one has to set the conditions and then explain how these are different from all the other times the Imperium faltered and didn't fall.

I mean, I guess it's like Imperial Rome. According to Gibbon, it was "falling" from the get-go, except that it wasn't, and the eastern half lasted another 1,000 years.

Arguably the greatest factor in Terra's survival as that all its rivals hate each other as much if not more than Terra.

I will add that I personally wish GW would back off the Space Marines a bit and pump up some of the other lists. Marines are always going to see steady sales, so why not convince players to branch out into some of the other stuff? A Necron/Tyranid throwdown would be fun and you could have other factions get involved in supporting roles.

Commissar von Toussaint wrote:

Breton wrote:
I think you missed my first sentence and the last one. Its not just the Nids and While Maintaining the Status Quo. Cadia fell, what changed? Not much. The only big changes are to make the status quo standoff more immersive.

No, I saw it but had no idea what happened because I'm not that up on the lore these days. Best not to quote something you know nothing about.

Biggest change so far? One Creed disappeared, and a new Creed took it's place. It was kind of like a Rocky franchise.

Arguably the greatest factor in Terra's survival as that all its rivals hate each other as much if not more than Terra.

Somewhat the point I made about Chaos having a tougher go, because even if you think there's a big drop from IF Primarch to IF Chapter Master, and Perturabo gets to lead the assault - his and others' egos will get in the way and there's no Horus figure to be the final word.

I will add that I personally wish GW would back off the Space Marines a bit and pump up some of the other lists. Marines are always going to see steady sales, so why not convince players to branch out into some of the other stuff? A Necron/Tyranid throwdown would be fun and you could have other factions get involved in supporting roles.

I'm all for mixing up other factions in the starter sets, but I'm realist enough to know one of the factions will be Imperium. Sales, Marketing, and Moms all point to needing some sort of anthropomorphic faction that little Timmy can identify with and Mom won't object to. Its a hard sell to say "These are giant deadly space bugs like you would have seen in the movie Alien, and they're fighting giant mechanical Egyptian Terminators". How many boxes would you like for your 12 year old son who can't see either of those movies in the theater? IG versus Nids as Starship Troopers is easier, because Mom knows the models can't take their uniforms off in a co-ed shower.

There's also the Terminus Decree to consider, a Grey Knights artifact that is most likely the secret to activating the Talisman of Seven Hammers. The later being a dead mans switch created and installed by Vulkan on the Golden Throne. Should the Talisman be activated, Terra would be consumed in a monstrous amount of the Emperor's stored psychic fire, destroying the planet, and sending a wave of his death energy into the Imperial Webway gate. Its said this would deal Chaos a severe blow.

I don't think the Emperor being killed would open another eye of terror, It would be awful due to the loss of the Astronomicon, but it would probably benefit the Imperium as well by weakening Chaos, assuming the whole Terminus Decree stuff is involved.

 Midnightdeathblade wrote:
There's also the Terminus Decree to consider, a Grey Knights artifact that is most likely the secret to activating the Talisman of Seven Hammers. The later being a dead mans switch created and installed by Vulkan on the Golden Throne. Should the Talisman be activated, Terra would be consumed in a monstrous amount of the Emperor's stored psychic fire, destroying the planet, and sending a wave of his death energy into the Imperial Webway gate. Its said this would deal Chaos a severe blow.

I don't think the Emperor being killed would open another eye of terror, It would be awful due to the loss of the Astronomicon, but it would probably benefit the Imperium as well by weakening Chaos, assuming the whole Terminus Decree stuff is involved.

That's the 40K AOS reboot GW has in their back pocket.

The Emperor Dies. The Emperor is a Perpetual. The Talisman of Seven Hammers goes off. Chaos is in full retreat, the Astronomicon is gone. The Emperor resurrects. Humanity regresses to the Second Age of Terra/Techology/Strife/Darkness, the Emperor creates new Primarchs, and on and on.

Perpetuals always come back, until they stop doing that, and stay dead. There is always some mcguffin. Ponteus or whatever, the guardsman who stood up to Horus, was a perpetual, until Horus stabbed him so hard he wasnt. The Primarch of the Salamanders was a perpetual until he fell into someting, and wasn't anymore.

Point is, the perpetual shield is the weakest armor the Emperor has.

The stuff about Ollanius Pius standing up to Horus might not even happen anymore. There's three different versions of the story with Pius, an Imperial Fist, and a Custodian all being said to have sacrificed themselves.
Oll Person (the individual that has been heavily implied will become Ollanius Pius) has shown up often but there is also the story of Ollanius Piers in Saturnine whose arc is intended to show the nature of myths and legends.

As for Vulkan, he hugged a huge psychic explosion on Ullanor during the War of the Beast and his body was never found. Considering he has been literally stripped to his component atoms before and come back to life, there's a slim chance he's actually dead.

If you could establish a blockade around Terra, even if only for a short time, couldn't you stop the Emperor getting his 1000 pyskers a day?

Although I guess its not known whether there's a few million or so there already waiting on ice.

 Mad Doc Grotsnik wrote:

FezzikDaBullgryn wrote:
The Necrons can do it without ever even entering real space, right? They have weapons like the death mark that can fire their guns from dimensions we can't even perceive, like the 4th and 5th dimensions.

Deathmarks can skip between dimensions, but so far as I’m aware, their guns can’t shoot between them.

Assuming you don't care too much about keeping the ship, given the damage you can do, what's to stop them skipping a ship into range and then firing on Terra before being destroyed? You presumably don't need long for the barrage and unless you're really unlucky, you'd have a few moments before any response would happen.


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Tyel wrote:
If you could establish a blockade around Terra, even if only for a short time, couldn't you stop the Emperor getting his 1000 pyskers a day?

Although I guess its not known whether there's a few million or so there already waiting on ice.

Given the scale of everything, there's presumably a huge logistic operation with very little redundancy, so you may not need to destroy many incoming supply ships to cause problems.

Since Terra is a billion strong fortress with no resources of it's own, you'd probably only need to take out a comparatively small number of food supply ships to cause complete chaos as different factions vie to survive.

I have no idea what security is like since the set up is pretty much to prevent invasion, but presumably a few imperial traitors could slip in amongst the countless nameless and faceless troops and cause chaos with some well place sabotage. A pilot crashing a grain barge in orbit, a grain store getting flooded, power for a sector failing, a PDF troop catching a contagious virus and so on.


How is the kill switch on the throne set up? Does it just blow if the Emperor stops breathing, or could he be starved out?

Breton wrote:

 Midnightdeathblade wrote:
There's also the Terminus Decree to consider, a Grey Knights artifact that is most likely the secret to activating the Talisman of Seven Hammers. The later being a dead mans switch created and installed by Vulkan on the Golden Throne. Should the Talisman be activated, Terra would be consumed in a monstrous amount of the Emperor's stored psychic fire, destroying the planet, and sending a wave of his death energy into the Imperial Webway gate. Its said this would deal Chaos a severe blow.

I don't think the Emperor being killed would open another eye of terror, It would be awful due to the loss of the Astronomicon, but it would probably benefit the Imperium as well by weakening Chaos, assuming the whole Terminus Decree stuff is involved.

That's the 40K AOS reboot GW has in their back pocket.

The Emperor Dies. The Emperor is a Perpetual. The Talisman of Seven Hammers goes off. Chaos is in full retreat, the Astronomicon is gone. The Emperor resurrects. Humanity regresses to the Second Age of Terra/Techology/Strife/Darkness, the Emperor creates new Primarchs, and on and on.

I'd honestly be down for some of that. Chaos should take the backseat and Tyranids should be front and center big bads.


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 Gert wrote:

As for Vulkan, he hugged a huge psychic explosion on Ullanor during the War of the Beast and his body was never found. Considering he has been literally stripped to his component atoms before and come back to life, there's a slim chance he's actually dead.

Him getting atomized really sends the plot armor of perpetuals to the moon and back. Atomization was the argument on whether they can be truly killed by lots of nerds before.

Wolverine can do it!

And it seems to be more a spiritual thing in 40K. Provided the soul remains intact then, like Dark Eldar, the rest can be grown back. Though I think in the Heresy novels it’s a bit more instantaneous than that? Haven’t read them all, and those I have I’ve not read in yonks.

Given the scale of everything, there's presumably a huge logistic operation with very little redundancy, so you may not need to destroy many incoming supply ships to cause problems.

I disagree. Just-in-time delivery is not the norm. It was a fleeting thing caused during the atypical peace and prosperity of the 1990s.

Stockpiles are how things are actually done. At a 1,000 psykers a day, I wouldn't be surprised if there were millions sitting in camps. I mean they're not frozen food, they're living herds and may be put to other work whilst they wait their turn just like any other livestock.

Similarly, iron rations can be remarkably compact. Given the paranoia of the Imperium, I'd bet they have a century's worth of biscuits buried in salt caverns.

This is an empire that has lasted for 10,000 years. That's not the sort of thing that collapses simply because the boss' pizza is a day late.

Him getting atomized really sends the plot armor of perpetuals to the moon and back. Atomization was the argument on whether they can be truly killed by lots of nerds before.

Its the Wolvering Atomic Bomb thing. Probably where they got the idea for Perpetuals in the first place.

Commissar von Toussaint wrote:

Given the scale of everything, there's presumably a huge logistic operation with very little redundancy, so you may not need to destroy many incoming supply ships to cause problems.

I disagree. Just-in-time delivery is not the norm. It was a fleeting thing caused during the atypical peace and prosperity of the 1990s.

Stockpiles are how things are actually done. At a 1,000 psykers a day, I wouldn't be surprised if there were millions sitting in camps. I mean they're not frozen food, they're living herds and may be put to other work whilst they wait their turn just like any other livestock.

Similarly, iron rations can be remarkably compact. Given the paranoia of the Imperium, I'd bet they have a century's worth of biscuits buried in salt caverns.

This is an empire that has lasted for 10,000 years. That's not the sort of thing that collapses simply because the boss' pizza is a day late.

The Vaults of Terra novel series shows there are no food stockpiles. The Inquisitor in the series institutes a temporary block on some transshipment from some orbital stations for plot reasons. He notes that any delays will result in people on Terra starving. This basically means Terra has no reserves and is always on the cusp of starvation. Now it would be the poor and destitute on Terra that would start starving because they would be the lowest priority to get any food. In any prolonged crisis, the upper classes would no doubt get any food first before any of the masses. So Terra wouldn't immediately fall from delays or cutting off of food shipments, but the poor would start off starving and there would be increasing levels of unrest until eventual full on revolt.

Stockpiles only work to an extent - if you have starving people and mountains of food you'd need to guard it too.

For a planet with no production facilities at all and a population of 1 billion, how long do you reckon it would normally be able to hold stores for?

A human eats about 4kg of food a day, so even if you assume a starvation died of half of that, that's still 2,000,000 tons of food a day. All delivered from off world.

I don't actually know how much food you can put in an Imperial cargo ship, but I'm assuming we're talking about many ships a day.

And that's just food. Does Terra produce water? Because that's the same again.

And any materials for anything else.

Iracundus wrote:
The Vaults of Terra novel series shows there are no food stockpiles. The Inquisitor in the series institutes a temporary block on some transshipment from some orbital stations for plot reasons. He notes that any delays will result in people on Terra starving. This basically means Terra has no reserves and is always on the cusp of starvation. Now it would be the poor and destitute on Terra that would start starving because they would be the lowest priority to get any food. In any prolonged crisis, the upper classes would no doubt get any food first before any of the masses. So Terra wouldn't immediately fall from delays or cutting off of food shipments, but the poor would start off starving and there would be increasing levels of unrest until eventual full on revolt.

First, Vault of Terra books tend to land on grimdumb side of plot. So, they aren't that good proof for that. Second, if there was a genuine siege/food crisis, the Terra PDF command wouldn't be sitting on their asses waiting for revolt but would actually start arresting most disposable stratas of society and start feeding them to corpse starch reactors to make sure there is enough food by increasing supply and decreasing demand. Hell, given how many supposedly surplus people in the form of pilgrims and such are on Terra it's probably the only world in the Imperium that can actually last a pretty long time operating on normal level even if the food supply is completely cut in an instant (and for that you'd need to not only cut Terran system from the rest of IoM, but also Terra from the other planets/space infrastructure in Sol system which would require even bigger force)...

Commissar von Toussaint wrote:
It was a fleeting thing caused during the atypical peace and prosperity of the 1990s.

No. It's caused by greed and cutting corners. Warehouses are expensive, so we should get rid of them and start bullying weaker subcontractors to make sure they are the ones suffering costs and getting hit on the bottom line while we give billions in bonuses to execs. At least that's how JIT works in the west. Original JIT, the one invented in Japan, was about optimization. It's worth noting the Asian companies that introduced it not only had relationship of trust, not abuse, with their suppliers that often lasted decades by that point, but they also invested money saved on the warehouses into subcontractors to harden supply chains and ensure no disruption happens. They even often paid a lot to bail out said subcontractors from trouble, but the JIT copycats here failed to get that part so their screwed up JIT implementation generated endless issues and smeared the name of otherwise sound concept.

Does Terra have any edible wildlife, beyond humans?

Because I'd assume anywhere with humans will at least have rats.

Didn't one of the BRBs state that every square inch of Terra's surface had been used for something? I.E. there is no buildable surface left on Earth any longer. It's either streets, spires, factories, or oceans.

I fully admit I might be wrong, but I'll go back through my BRBs and check.

Breton wrote:
Not the biggest stretch to make Terra a Tomb World so the Necrons are already there and just haven't woken up Tutankenhamen The First King yet.

Couldn't they just time travel to take it over first?

On blockading Terra? Whilst possible, you still have the not inconsiderable task of not just containing but destroying the collective space borne defenders of the Sol System.

To the best of my knowledge, to blockade any system in 40K you deploy picket fleets to the Mandeville point.

Given Mandeville Points depend on things from gravity wells to maybe not ripping a hole in reality right next to my outside lavvy, thank you , they’re inherently mutable and the exact location/definition will vary system to system.

And, whilst I cannot provide particular citation? I’d wager the Sol System is well defended enough to not only picket/monitor it’s Mandeville points (at least to the point of detecting incoming craft), but with more than enough resources to simply blat opportunistic/accidental attempts.

So I feel we again have to come back to considering “just how many ships are based in the Sol System”.

The lazy answer is of course ‘finite’. So it is possible a wily attacker, with sufficient resources of their own, could launch waves of incursions across the Mandeville Point, drawing ever more defending ships to contain them.

Then, not giving a fig for sensible, deliver a strike fleet powerful enough to overwhelm Terra’s planetside defences. Which given its critical nature to The Imperium, and not worrying about any “tHeN tEh EmPrAh SeZ NaH” lazy Deus Ex, we have to assume is……far from an easy task.

Of the various forces out there, I’d wager only four might have the resources to do that. Namely, and in no particular order? Orks, Necrons, Chaos and Tyranids.

One has the particular desire - Chaos. But seems to lack the necessary unity to fulfil my criteria above. Because how do you arrange the sacrificial fleets - attacking Terra mark you - to allow your main fleet to drop in an have a proper go.

Orks most definitely, on a galactic scale, have the numbers. And if Da Emprah’s home address became Orky Knowledge, they could most likely get waaay more than enough numbers together. But they still, to the best of my knowledge, entirely lack reliable Warp Navigation. But Waaagh! being Waaagh! it could be done, even if it’s by degrees and sheer bloody minded attrition.

Nids seem the most likely candidate. So far as we know, The Astronomicon is the flame to their moth. It might take them a long, long time to work their way there, but they seem pretty inexorable in that task.

 Adeptekon wrote:
Couldn't they just time travel to take it over first?

Time manipulation is a skill that very few advanced Crypteks can attempt, such as Orikan the Diviner, but actual time travel isn't possible outside of random bad luck thanks to Warp travel AFAIK.
That being said if it was, it would be one of those things that the Necrons could do but don't because etiquette, like with the Celestial Orrery where the ruling Overlord could just destroy Sol and get a cheeky win but it's rude and unsportsmanlike to supernova a species home system.

 Gert wrote:

 Adeptekon wrote:
Couldn't they just time travel to take it over first?

Time manipulation is a skill that very few advanced Crypteks can attempt, such as Orikan the Diviner, but actual time travel isn't possible outside of random bad luck thanks to Warp travel AFAIK.
That being said if it was, it would be one of those things that the Necrons could do but don't because etiquette, like with the Celestial Orrery where the ruling Overlord could just destroy Sol and get a cheeky win but it's rude and unsportsmanlike to supernova a species home system.

There’s also the sheer tapestry of time and chaos theory.

As things stand? Whilst far from ideal, things aren’t that bad for the Necron race.

Whilst I suspect their chronotech could allow such a thing, preventing The Imperium could make things far worse in ways we cannot properly consider.

There's an actual Necron time machine which sends some genestealers back prior to biotransference in Devourer.

The Necrons just never used that technology for anything important because OH LOOK AT THAT OVER THERE...

The Necrons aren't generally idiots though. Well apart from that one time but building super weapons that break the fabric of time and space are sort of a hobby rather than a serious threat.
They act as a deterant to other Dynasties but their owners also know if they try any funny business they've got a boat load of enemies and even with fancy gizmos they can't stop them all. Plus the Triarch Praetorians tend to make sure these sorts of things don't happen with very real threats of "If you push your luck we will delete your System 32".

 Gert wrote:
It depends I would say. The size of the Hive Fleet required to take the Sol System would be immense and the losses would be massive.

Not necessarily. When a hive fleet is on approach they cause massive natural disasters on the planet and drive psykers crazy. Which could severely weaken Terra's defences. There's also the GSC already present on Terra, which would become even more active once the hive mind alerts them. I'm not saying it's going to make the battle easy, but it seems to be something not being considered.

Luna, Terra's orbital defences, and the Sol fleet are it's best defences.

 Irbis wrote:

First, Vault of Terra books tend to land on grimdumb side of plot. So, they aren't that good proof for that. Second, if there was a genuine siege/food crisis, the Terra PDF command wouldn't be sitting on their asses waiting for revolt but would actually start arresting most disposable stratas of society and start feeding them to corpse starch reactors to make sure there is enough food by increasing supply and decreasing demand. Hell, given how many supposedly surplus people in the form of pilgrims and such are on Terra it's probably the only world in the Imperium that can actually last a pretty long time operating on normal level even if the food supply is completely cut in an instant (and for that you'd need to not only cut Terran system from the rest of IoM, but also Terra from the other planets/space infrastructure in Sol system which would require even bigger force)...

One of the problems with GW fluff is that people are allowed to write authoritatively on things they know nothing about.

Given the totalitarian nature of the Imperium, I would expect everyone on Terra to have a very good reason to be on Terra or they would be deported on outbound Black Ships. Remember: no one likes empty ships. I suspect that's how the balance is maintained - bring in 100,000 psykers and take off 100,000 "useless mouths."

No. It's caused by greed and cutting corners.

What I meant is that it was only possible for that very narrow sliver of time when great power rivalries had disappeared and advances in transit, communication and computing allowed for it to be set up. Prior to that time, it wasn't an option even if you wanted it.

Given that Warp storms are a thing, Terra would have massive reserve stocks. It is the seat of the Emperor, and the sole source of navigation for all humanity. A planet like that would be maintained in permanent preparation for a siege.

Commissar von Toussaint wrote:

 Irbis wrote:

First, Vault of Terra books tend to land on grimdumb side of plot. So, they aren't that good proof for that. Second, if there was a genuine siege/food crisis, the Terra PDF command wouldn't be sitting on their asses waiting for revolt but would actually start arresting most disposable stratas of society and start feeding them to corpse starch reactors to make sure there is enough food by increasing supply and decreasing demand. Hell, given how many supposedly surplus people in the form of pilgrims and such are on Terra it's probably the only world in the Imperium that can actually last a pretty long time operating on normal level even if the food supply is completely cut in an instant (and for that you'd need to not only cut Terran system from the rest of IoM, but also Terra from the other planets/space infrastructure in Sol system which would require even bigger force)...

One of the problems with GW fluff is that people are allowed to write authoritatively on things they know nothing about.

Given the totalitarian nature of the Imperium, I would expect everyone on Terra to have a very good reason to be on Terra or they would be deported on outbound Black Ships. Remember: no one likes empty ships. I suspect that's how the balance is maintained - bring in 100,000 psykers and take off 100,000 "useless mouths."

You're forgetting the corruption and the snobbery. The unwashed masses are out of sight out of mind for the upper crust, the lower crust will use them and only ship off the ones that aren't protected by them or someone else.