When you say self-taught do you mean even without using a really good text? Or do you mean that it actually can't be taught without a teacher? If you are saying that math can't be taught without a good teacher I don't really see how that is "known".
Even if it requires a good teacher, does society benefit from forcing it on individuals at a time they don't want to learn it? Or would we be better served by making good teachers available to those who want to learn it, at the time they want to learn it?
I'd -love- to go through some of my college level math classes; both the ones I took, and the ones i didn't need to take. They weren't especially relevant then. They're slightly more now, but more than that, I'm -interested- now. But self-learning takes too much of an investment of time (when I run into something I don't know I have to research -that-, and it becomes this infinite process of diving down rabbit holes, rather than having someone who has gone before who can give me a sufficient answer to unblock me on my original question).