More than that, many degrees (especially in the liberal arts) are, economically speaking, luxury goods. They may teach things that benefit society on some level, but the cost of procuring them isn't offset by low wages and scarcity of the relevant jobs.

In a way, they form a bit of a poverty / class mobility trap for those who aren't well off enough to afford them on their own but are attracted by the idea of a purpose-driven life (social work, librarian, historian, identity studies come to mind).