I call it the Bogdanovitch Syndrome.
Dweeby director/writer gets on the Hollywood A-List. All of a sudden the girls he could only dream about in high school are throwing themselves at him. He loses all judgement and proportion. He thinks himself a genius and starts treating the people who kept him centered like flunkies. It's all downhill from there.
Moore really began seeing himself as some kind of kingmaker, as the leader of the American Left since Jesse Jackson (Ever see A Face in the Crowd ? That was a great 50's movie where a Andy Griffith played a folksy kind of Will Rogers who is plucked from nothing, given a TV show, becomes a superstar, goes powermad, thinks he can pick the next president, alienates everyone around him with his newfound megalomania, and is ruined by it.).
Absolutely great movie. But Lonesome Rhodes (Griffith) was a shiftless manipulator from the very start....