Link: http://sports.espn.go.com/espn/page2/story?page=easterbrook/071218

...in which he dissects the myth of the Super-Coach in football. As he points out, the myth is pervasive for a number of reasons, not the least that if you can personalize the biggest factor in group performance down to one person, it is easier to hire and fire one person than a whole group.
I have seen that at work in corporations for decades. CEOs get paid way too much money and have a lot less impact than many people think they do. I would actually venture to say that senior leaders in all contexts have a good deal less positive impact than they think they do, but can have a bigger negative impact. My employer fired its CEO in 2003 after he helped the stock price off a cliff, but employee morale was drastically weakened during his tenure due to his tendency to treat employees as disposable commodities. That sort of approach is more damaging than any amount of positive behaviour.