You put it quite well. The usual solution to the imagined problem is a return to simpler times and something like pioneer self sufficiency - good luck with that. Of course, the thinking goes that good luck will occur, provided you have enough ammo to defend your stash. The imagined failure is often conceived of as a sudden catastrophic collapse of all order, with complete, everyone for themselves, dog eat dog existence. Probably not so much.

I am reminded of a famous line - "this is the way the world ends - not with a bang, but a whimper" ts eliot??