We (America) made university educations super expensive. Causality is complicated, but it probably started as an effort to destroy the anti-war movement in the 70's.
When we're talking about college costs, public schools are really the only institutions that matter. The Ivies (or even Ivy+) are a rounding error compared to the big midwestern land-grant universities and the UC and Cal State systems.
States have substantially reduced their per-student support for universities: https://www.ppic.org/publication/higher-education-funding-in...
This coincides with federal funding programs, but student loans are famously not dischargeable, which makes them more instruments of social control than conventional financial vehicles.