A lot of people don't have the luxury of spending tens of thousands (or in some cases hundreds of thousands) of dollars and, more importantly, several years of earning potential to just "learn things."
That's not to say that all or most people don't want to "learn things". But they're smart enough to realize that they can't afford to do that. What they may want to do, though, is support themselves and possibly live something approaching a middle-class lifestyle.
Many students are smart enough to realize, as well, that if you can get a good job and financial security, you can afford to have free time to do things that interest you. If you're scraping by in a dead-end job, it's a lot tougher to have hobbies or do any other sort of self-improvement.
And so they go to college, because they've been told over and over again that college is 'the best investment you can make.'
In some cases, that advice is coming in good faith from older people who grew up when a 4-year college degree basically was a Golden Ticket into the comfortable middle class. In other cases, it's coming from 'admissions counselors' (aka 'recruiters') whose job it is to get signups in order to bring in Federal loan money. What you don't hear from either group is that a college degree appears to be a declining asset; as more people have them, the benefit of having one (in terms of standing out in the hiring pool) goes down, at the same time the cost on average has outpaced inflation.
It's a shitty situation all around, and I'm honestly not sure what the best advice is to give a young person today. But one thing I am sure of, and it's that the old canard about "study what you love, the job will follow" is a lie. If nobody will pay you to do what you love, don't pay a lot of money for a piece of paper that says you're an expert in it.