I think there's diminishing returns. A broad, liberal arts, undergraduate education develops critical thinking and reading skills in a zero-to-one kind of way. Once you've attained those skills (whether through a college degree or some other way), further enrichment via self-study is much more easily doable.
This is definitely true. I think pre-graduate college is pretty eye opening, at least when I went. In most high schools, they just cover the top layer of knowledge; in college they go quite a bit deeper. "They never taught us that in high school," is a saying that applies.
