Jobs, Cook, other CEOs -- we fall into fundamental attribution error [1] when we give them too much credit for the success of a company, something Americans are particularly susceptible to (which I say as an American). Not infrequently the best thing they can do is to get out of the way. By contrast, a bad CEO can do much to sink a company.
The entire definition of being a leader is that you are individually held responsible for the results of everyone you lead. It's not fair, but it works because holding someone to that level of responsibility and the level of autonomy that goes with it means they can use all their creativity and resourcefulness to deliver results and overcome obstacles.
[1] http://en.wikipedia.org/wiki/Fundamental_attribution_error
EDIT: clarify meaning.