I think we sometimes forget the immaturity of youth. They don't have the life experiences parents have about what it takes to be successful. They don't know how to prioritize. They can get lazy and distracted. So it is easy to say, if he loves it, he'll do it. And certainly some kids have that. But a whole lot of other need a "nudge" here and there to learn about working hard, sacrifice and prioritization.
I was watching recently elected Hall of Fame football player Michael Strahan today. He told a story about how we wanted to quit after his first year of college. His dad "suggested" it wasn't a good idea. The rest is history.