Often its their willingness to take big chances that gets them to the top of their market. But once they get there (especially after going public) the "adult supervision" takes over and they lose what made them successful in the first place almost as soon as the finance professionals or sales people take over.
I'm not sure why it's so hard to understand that technology companies should be run by technology professionals. Would anyone walk into a hospital and suggest that it should be run by someone other than a doctor?
Of course any successful tech company should employ finance professionals, but they should help the company achieve its mission, not define the mission.