> If we went back to recording lectures by the worlds best and putting it online for free with attached books and exercises, we could improve the world a lot.
How is that a viable model?
Making the world a better place sometimes is incompatible with a profitable business model, that's why donations still exist.
Maybe improving the world is a good idea regardless of whether it's a viable model?
Anyway, in this case, the cost to the university is quite low and there's no real loss of income, as the real value the vast majority of people pay for is clearly in the status that comes from being there in person and getting the diploma.