When President Biden canceled college debt last month, he left untouched the problem that created that debt: the soaring price of college.

In the 1980s, the list price of undergraduate education at a private four-year institution could hit $20,000 a year. At some of these schools in the last couple of years, it has topped $80,000.

Why has a college education become increasingly costly, and why has that become such a difficult problem to solve?