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

When you allow nearly unlimited government funds into a business, management expands.

Lazy rivers, apartment-style dorms, Office of Diversity, Equity & Inclusion, etc. These extras that schools have now don't get paid for with wishful thinking. Hell, here's $400k-$500k per year being spent now which wasn't deemed as necessary until the last twenty years or so.

Here's just the top level org chart for LSU: LINK It would be interesting to see how different the one from 1970 or 1980 looked. I imagine there wouldn't be quite as many positions. If you were to drill down, I imagine you would see even larger discrepancies between the amount of non-teaching employees now versus then.