I think those classes are from a bygone era of when college was affordable and you could take a course "just to learn". Higher ed today is very different, I almost look at colleges are higher level trade schools if you're in CS, Engineering, etc.
In other words, I don’t think that “broaden your horizons” is the issue. But rather that liberal arts education is not the way to do that.
The current situation - colleges as trade schools, as you aptly put it - suits educational institutions quite well. Businesses like it, as well, because they can outsource early-career job training. It's only for, you know, actual people that the system doesn't work anymore.
They won't need to "do", they are here to "be".
John Adams to Abigail Adams, May 1780
Ah yes, that bygone economic era of prosperity. In it's place today, a shrinking economy, one must posit from your comment? Surely current economics show a great decline in prosperity?
Life is about balance, and while I can quibble over the last part of your statement, I do agree that more needs to be done to expand student access to non-program classes. Even students within a college or school don't always have access to every course being taught if it's outside of their chosen track, and that siloing isn't good for producing well-rounded, interdisciplinary-minded people.