I think it might be a slightly wasteful system. I havent dug deep but this article with numbers from 2017 seems to hint that it’s not all to pay better teachers. E.g:

A study found that the California State University system had 11,614 full-time faculty in 1973, and 12,019 in 2008. During that same time period, administrators grew from 3,800 to 12,183, ending up with more administrators than faculty.