We have too few great colleges around for the potential population. Should really be building more colleges and expanding the existing ones. MOOC's and open educational content are an inefficient band-aid, in-person instruction should always be preferred.
The colleges we have are too expensive. They tend to bundle up sports/research/culture/medicine/whatever/education. Students have to pay tuition to support all that. If you're strapped for cash, there's not really a way to opt out of all the bonus content and just get the education.
Artificial constraint of supply by elite colleges.
With Endowments well into the tens of $Billions there is no reason schools like Harvard, Princeton, Stanford, Yale, Etc. can't have freshman classes of 10,000 instead of 2,000.
