this is true with any sport, once you get to a certain level you have to commit 100% of your time and energy if you want to distinguish yourself and become the best. it's hard because you can't get to that level and have a normal, balanced lifestyle, because there just isn't enough time for everything.
I think that's why a lot of kids that start out with a lot of potential end up just dropping out, because they just aren't willing to commit that much time and energy to one thing and sacrifice living a normal life.