Back in the day, almost every family that sent a child to an expensive, elite college already was rich.
“Liberal education” meant educating people for a life of liberty, which is to say for a life of never needing to work a single day, or to take orders from anyone else … unless one freely chose to do so. Much of the liberal arts curriculum still derives from classical ideas about educating an aristocracy for the disciplined use of leisure time. Except that today, an average schlub can get the kind of education meant for the 1% when it was invented.
On the other hand, our economy has become very knowledge-driven. Creating and sharing knowledge are at the heart of what modern universities are supposed to do. The best colleges not only teach existing knowledge, but also help students learn how to create and share new knowledge. Governments, companies, and investors do pay good money for that ability.