Comment by chongli
The signalling hypothesis (of Bryan Caplan [1]) lurks within your two premises. Neither the poorly regarded party school nor Harvard add much in the way of human capital. What both do is act as honest signals of intelligence, ability, conscientiousness, and resourcefulness (including family resources). These are extremely valuable indicators for prospective employers who are otherwise prohibited (by law) from asking or testing these directly and punished (through wasted wages, training costs, benefits) for making a mistake.
In the past it was much cheaper to train people on the job because wages and benefits were much lower. Higher education has driven up wages and benefit costs (through inflation and cost disease), thus cementing higher education’s position as a gatekeeper.
[1] https://en.wikipedia.org/wiki/The_Case_Against_Education?wpr...
I certainly learned a lot of mathematics at university that I probably wouldn’t have learned without it. Perhaps more importantly was some amount of mathematical maturity. The former has probably not been that useful in my career (idk maybe some linear algebra?) and the latter maybe a little bit, but if one were trying to figure out the optimal things to learn for my job, they probably wouldn’t have been what I studied.