The move from centralised affluence to fragmented stockades housing war bands and king-lings happened within a single lifetime, and was very hard to miss.
The closest modern equivalent would be post-Soviet Russia, with the war-bands replaced by local mafiosos. Russia had some reslience because there was something of a tradition of self-reliance and barter before everyone's pay dried up. But what happened in Russia was hardly pretty.
A similar change in the West would be much more catastrophic, because hardly anyone has similar experience of self-sufficiency, population densities are often much higher - especiallly in the UK - and most people would be in shock if they could no longer buy essentials from supermarkets.
As for comparing a putative future collapse of The West™ to that of the Soviet Union, there's this lecture by Dmitry Orlov (I think I first got a link to that from ET, but I don't know in what thread). "It's the statue, man, The Statue."
If you were a merchant or someone else in the middle classes, I'd expect that it was very catastrophic indeed. If you were one of the peasants, possibly not so much.
The ruling elites were either slaughtered or adapted to new masters - which would doubtless have been catastrophic for them too.
We are schooled to think the Fall of Rome was a Bad Thing. Un-privileging the Roman POV allows for a broader, better, analysis.
