I think part of it is that unlike in the US, access to education wasn't paywalled.

Higher education in the US, with the exception of scholarships here and there, requires you to come from a wealthy background to afford the best schools.

In other words, it's more about perpetuating class privilege than it is about developing the best and brightest of a generation. If you're a genius with poor parents, you have to really hope to get lucky enough to get a scholarship.

In socialist societies, despite the claims often leveled against them, things were more meritocratic. If you're a genius with poor parents, you got access to the best education as that's what's optimal for society.