theory

It's a fair question, we didn't get any revolutions in those places. And after the destruction of revolutions elsewhere it's going to be even less likely in the seats of the empire.

From reading biographies of US presidents, it seems like there was a fairly widespread belief that socialism was just what came next, eventually. At the time people were creating and reading these theories, there was a sense that it was inevitable. Industrialization and pollution were visibly awful, labour laws non-existent.

Ultimately in the West/global north concessions were made to stymie revolution. They were unsustainable as we know - built upon unequal exchange abroad, domestic underclasses in many cases, enforced by militarism and interference. Those concessions also depended on a ruling class which is now largely dead and been replaced with a decent number of true believers who've inherited it, who bought the market mythology wholesale and think it's actually how things were working.

I mean, my perspective is is that these people really just wanted a revolution at home, in the places they'd known and lived in, and didn't really know what outside of Europe was like mixed in with a ton of yt supremacy.

Even if they were ultimately incorrect and coping, it's understandable that if they were European they wouldn't know other conditions well enough to make any predictions outside their bubble.