Leadership plays a part but honestly...These guys are all leaders on some level. They need to be able to drive and motivate themselves, individually.
do you mention that because of the fact they've reached the NHL?
if so, I'll tell you that i've had the opportunity to work alongside elite world class athletes from a broad spectrum of sports, and I'd argue that while it's almost a given that athletes have more drive/motivation than the average person (at least people who aren't involved in a pursuit where competition is the name of the game... i have no doubt that many professions outside the sports world demand highly motivated/driven people), the difference in those qualities BETWEEN athletes who have reached a similar level of competition (in this case the NHL), is almost astounding.
Some athletes really do get by on huge amounts of natural talent, or from having grown up in ideal settings for that sport (early coaching/parenting/competitive environments), and amazingly, sometimes even some of the most successful athletes are no where near as driven as you'd expect them to be, at least not in comparison to some of their rivals.
In a team sport, this disparity of natural/innate motivation can sometimes be staggering, and I think it's why you see the emergence of "great leaders", other athletes who are able to raise the level of drive/motivation of their teammates... a task that can be incredibly difficult depending on the general make-up of a given group.
being motivated enough to get to the NHL is not the same thing as being motivated enough to WIN in the NHL...