I think that people have such different ideas about what college is for that it's hard to say what other people should do. The best advice I've ever read about college was here - and the comments are full of people denouncing it as terrible advice! Chacun à son goût.
For myself, I wish I'd switched from maths to economics.
When you notice that the higher education system has too many different purposes, I guess it would be a good idea to stop thinking about it as an indivisible system where every university has to have a similar purpose. Maybe different colleges and universities should specialize in satisfying different purposes? Of course, even today some universities (at least to some extent) do that. However, maybe making it explicit which university is of which type would stop them trying (or pretending to try) to cover everything? In the best case scenario, those different types of universities and colleges would compete for prestige with other universities within the same type.
I was looking at a discussion of what should be in a college curriculum, and as such discussions seem to go, there was a big list of things everyone should study, and some political claims about what's being offered but shouldn't be.
Instead, what do you wish you'd studied in college? What do you wish other people had studied in college? On the latter, do you think everyone should have studied it, or do you just wish more people knew about it? Approximately what percentage of people?
Of course, this doesn't have to be limited to college. People could learn the same things earlier or later.