Who else remembers the
GW vehicle made from a deodorant container?
https://spikeybits.com/2015/06/1-famous-40k-conversion-flashback.html
Osprey Games recently released The Doomed (sp?) miniature skirmish ruleset, and one of its selling points was kitbashing. This suggests that, at least with miniatures, DIY isn't a thing, although for terrain and gaming boards, I'm still seeing a lot of DIY, perhaps because of the cost.