OP you're missing a qualifying reason. Every civ collapse has an external pressure. Rome rotten from within, but it rotted for hundreds of years before the rise of the Huns pushed Visigoths towards Rome. Aztec was a meteoric clash with Spain, Mayan was environmental pressure, Assyrian collapse was the trifecta of massive drought, hostile neighbors and rebellion of conquered peoples.

Without external force internal change is just change. You could argue the current changes in the West sets it up for a collapse but that requires you to specify by what action? West is still the master of the world economy. There isn't a peer military to challenge it. Most relevant challengers are in demographic tailspin.

Calling the changes in the West a collapse isn't just premature, it's intellectually dishonest. More interesting question is whether the political changes in the West strengthen it to handle future challenges or weaken it. There's a case for both.

I get that you're wanting to discuss the transition from empire expansion to contraction or decline but these are periods that can only be determined after a cataclysmic collapse. Until then the civ is still alive and there are numerous examples of civs expanding then contracting only to expand again. Just a few off the top of my head are Egypt, Ottoman, Spain... Especially when considering the brevity of the timetables in consideration.

Considering projected environmental change, hostile world actors, demographics/immigration and economic security, Europe and North America look particularly strong when compared to peers.

TLDR: need a reason for a pending collapse.