A "liberal education" originally meant that those who pursued it were free. They weren't pursuing an education of mere techniques, which was for slaves. Even today, there is a place for learning things that don't have a direct economic impact, as part of becoming an educated person.
That's from the more idealistic side of me. Now here comes the cynicism. Why? Because people still want to major in them, so that they can say that they have a college degree without having to major in something rigorour. And those people pay tuition. And the colleges like getting paid.