re: I don’t get why it is more costly for colleges to educate students now vs the 70s/80s

An increase in the number of staff leads to an increase in the overall operation costs of any business in any industry, of which big academia has become: soulless enterprises designed to churn out student debt quickly for maximum profits which, of course, leads to more bloat. The specific tenure bit is more of a commentary on unfireable holier-than-thous who believe that regurgitating the crap their cliques want to hear in order to obtain their precious positions means that absolutely nothing which falls out of their mealy mouths could ever be fallible. I'm sure that's not a direct reference about you, is it?