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.