Education is clearly a path to increased prosperity for many people, and they will pay a lot for education to try to distinguish themselves. And when it's nearly an expectation, it's not a completely voluntary purchase (like healthcare), so demand is quite inelastic and people will pay what is charged. (And also it is a spending choice at quite an early age when people are not great at thinking about whether taking on debt is a smart choice, etc)

My theory is that as our society matured, people/companies/institutions gradually figured out that education was something that they could extract value ($) from and take a cut out of. (Whether that is just blatant profit, or using the money to invest in education-related things, or even less insidious semi-reasonable employment of lots of people in that industry to benefit off of it. A gradual creeping up of somewhat well-intentioned desire to turn it from classes in just-good-enough lecture halls into polished buildings that need endowments and administrators to oversee.)

The problem is when goods that are pretty mandatory to succeed in life get turned to the for-profit market to be solved, of course prices will go up.

What we are increasingly failing at is to offer enough seats at high quality educational institutions at affordable prices. That's how you get out of this.