You make a great point. I, too, took piano lessons, ballet, and clarinet. You could argue that if I'd focused more on those skills I'd be better at them, perhaps even great. (Not sure about the ballet, but maybe the piano.) I don't think that you're saying anything very different from what I said: education can help you to determine what talents to focus on. I believe most people have multiple talents. The key is to determine which ones to focus on.

"Outliers" sounds like an interesting book. Certainly, nurturing talent is a valuable part of growing it. There are, of course, rare people who have such a gift that they don't need anything else, but I think those people are probably extraordinarily good observers, picking up on things themselves rather than needing someone to explain it.