Apologies, I took it all from Lexicanum just to make sure I had my facts straight, and it had what you quoted before what I found.
Certainly nobody would be thinking of a full army (at least, I hope they're not

) but even reasoning that the suits can be manufactured is almost unreasonable.
No need to argue, also from Lexicanum, under the Power Armour article - "It can take decades to complete just one of the new Mk VII power armour, so it is often easier to make a spare part for an existing suit than it is to make a completely new one".
If that's how long it takes for a Mk VIII, imagine how long it'd be for an older Mark, if it could even be constructed, of course.
G.A