You forgot one:
e) Not enough sycophants.
O'Leary comes from the make-believe world of television where he plays an all-knowing, can't-fool-me, successful businessman (his real business success record is questionable, however, ie O'Leary Funds). 
As a star, O'Leary can enjoy the adulation of obsequious  contestants, assistants, fans and wannabes. As a politician, he faces constant scrutiny and criticism -- and actually has to come up with something on his own, something that isn't scripted.
Kevin just decided to go back to pretend land -- it is a hell of a lot easier, and  more fun.