You really don't need to pay tuition to gain a rich education in art and humanities and sciences if you want one. There are resources aplenty - buy a book!

I'd even go so far as to say the majority of college grads learned almost nothing during college, and the few who did would, after a few years of maturity, pick up a book of their own free will and enrich themselves.

I think the costs of university (huge amounts of debt and enormous human and physical resources put into holding lectures in giant buildings that need to be maintained and heated, the social divide created between those who got to hang out among the privileged for 4 years and those who couldn't) generally outweighs the hypothetical benefits you mention that some people might gain during college. Except perhaps for a few fields (like medicine, or dramatical arts, or music) where you can't just pick up a textbook and learn it all.