I think what happened was western liberal establishments got politically greedy. Rather than admit policy errors and allow a periodic pulse of manageable reactionary venting as the natural consequence of those errors -- e.g. Farage-style governments in Germany, UK; a reelection of the first, softer version of Trumpism -- they allowed no "manageable venting" whatsoever. They didnt even acknowledge any past errors. This only caused deeper mass-frustration, bringing about the inevitability of a more extreme eruption down the road. The new dynamics held beneath the surface and coming to the fore are also much more evolutionarily advanced than the manageable venting which ought to have been permitted ever was. Tactics and concepts have been honed under harsh "Darwinian" pressure, while liberalism became complacent, senile and flabby.

Counterpoint (though I admit this is motivated reasoning, since I'm a professor, and one who has maybe 30 years left in the profession): 18-22s want to be in an institutionalized IRL spatial setting where they're with other 18-22s. That demand isn't going anywhere.

I lived in central Philly for a decade, and if I think about why I left, yes it was partly that COVID shuttered public transport which meant I had to get a car and I discovered that parking in central Philly is worse than dental torture. Yes, maybe it was the crime and disorder surge, which at least in my old neighborhood (Broad + South) predated COVID (began around 2018 or so). But the thing that pushed me away the most was the emerging monoculture, the total impossibility of escaping the Same Opinion on every sign, in every conversation, a constant feeling of being horizontally surveilled for wrongthink…terrible for trait openness, in which case the “charming artsy pedestrian friendly old urban core” loses a great deal of its appeal and just becomes claustrophobia inducing. Moved to suburbs, and these have all the problems I expected them to. But the ambience of neutrality makes it easier to hear one’s own thoughts.