Probably because guys like Crosby not only work hard, but they also know that to win, you need to work hard.
For some of the high end players, I don't think they realize they need to work hard - they just have to get 10% better - lol.
It's not just the work - it's the attitude that you will leave it all out there, you'll work those hard areas of the ice, and you'll sacrifice.
And you look around the league and teams that have those types of players usually play a hard game - it rubs off when the high skill players are the guys that get it.