Actually, there was an interesting link posted here a while back[1] that explored how non-profit colleges have a vested interest in making sure at least half of their students
cannot afford full tuition.
To keep their tax exempt status, they must act as a “charity” by extending financial aid to at least half of their students.
The tax-exempt status enables them to invest their endowment without paying taxes on the gains.
[1] https://news.ycombinator.com/item?id=18792515