Haha! Market economics and myths about degrees and particular institutions, and crucially the value of networking in professional life after university.
In reality much smaller, flatter structures than universities could provide the same (or better) standard of tertiary education. A lot of the seminars could possibly be done by skyping or hiring a cheap room locally. Lectures (if indeed they are ever genuinely needed) could be delivered by YouTube. This wouldn't prevent the possibility of social interaction with other students.
For most subjects these days, most learning is self-learning, done by reading books (and of course use of the Net).
What you are paying for is NOT quality of education, NOT face-time with your teachers and NOT lectures (you could get that info more efficiently by reading). Contrary to myth, the value of university is not even about "having a good time"/"so much more than education".
In reality you are paying for a piece of paper which says "Yale" or "London University" or whatever, and the value of that piece of paper is that potential employers regard it as a badge of seriousness, not of education.
The other thing you're paying for is to make friends. The idea is that subsequently they and/or you become moderately successful and help one another out.
And the level of the fees? They charge whatever they can get away with. Everything is now "marketised" (already in the Anglo-Saxon world, and the rest of the world will have to follow suite). Even if they didn't spend the money on staff salaries they would find ways: advertising and branding, preposterously expensive research facilities, Hadron coliders, sabbaticals... the list is endless: university managers are creative people in one way at least.