The assumption is that if there is something you need to know and you encounter a situation that requires it, you can learn it. And if it turns out you do not need it, you saved the time. Further, formal instruction only works for some types of people, albeit probably most. Synthesis from learning when you are interested tends to be more useful than memorization. The experienced part is the scary one, although in terms of spending time with peers, doing sports, art, etc. we did not really miss out on that.