A weak point in left thought to my mind is its widespread spontanaeism - the notion that once people just see how well other approaches work they'll naturally adopt them. While true to some extent I think it also rests on a sort of utilitarian rationalism and skates over the problem of incumbent actors operating in bad faith. So people either tend to avoid that question altogether (utopianism) or posit extreme solutions that take no account of tactical/strategic factors (ultras). If you delve into the work of statists like Bill Lind, in contrast, you don't have to look too far before coming on discussions of the practicalities of repression and how to implement it while maintaining strategic superiority.

The AI analysis is OK from that perspective - kinda like classical mechanics does a decent job of predicting local astronomical phenomena despite its explanatory limitations.

Also, claiming that communists tried to nurture a middle class is just plain wrong. Communists were, at least according to Communists, trying to abolish class entirely, and initially to uplift the proletariat, the working class.

Well, you could say lift them up into what? The middle class is in the middle between (stereotype warning) powerful idle elites and downtrodden industrial wage slaves/serfs. The Communist Manifesto sketches the idea of the future society out quite loosely, but it boils down to 'hey, we could actually provide a middle class lifestyle for everyone by rethinking property relations' - Marx talks about everyone putting in some work but also having meaningful amounts of leisure time . Presumably the heroes of a future communist society would be those who maximized consumer rather than producer surplus after externalities had been accounted for.

The goal wasn't to drag everyone down to the lowest pits of the working class, but to afford everyone the freedom from day-to-day economic insecurity and the dignity middle class people have historically enjoyed, without allowing new elites to coalesce. Think of post Kruschev Soviet media where there's a sort of technological and economic self-confidence on display.