College Professors don't exactly make the big bucks either.
Yet, universities in the US have made put many Americans in lifelong debt.
These colleges are all "nonprofit" (and get significant tax benefits), so where is the money even going?
Administrative staff, which has ballooned over the past several decades. Many of these people have mediocre ability, don't really do much, but once a position is created it is hardly ever eliminated.
Buildings and renovations. Ever seen a modern student dorm? They are luxurious compared to what they were in the 1980s. It's a constant competitive war as students will actually choose a school based on the living accomodations over the education.
Programs to assist students who should really not be there, and other programs that don't seem to recognize that college students are adults and should be expected to manage their lives by themselves. Do they really need the university to arrange coloring book time to help with the stress of mid-terms?
For people in many European countries, this is an absurd amount of debt to get a university degree.
Edit: For context: About 20 years ago, my university's annual fees was $15000/year for out of state students, and $4600 for in state - in today's dollars. Now that university charges $28K for out of state and $8.3K for in state - almost doubled after accounting for inflation. In other nearby universities I see people paying $15K/year for in state. This is a huge increase in two decades.