That's the way this business works: if your movies do well at the box office you will be offered more movies. It doesn't matter if you're a nice guy or you're a prick. If your movies do well there's a job waiting for you in Hollywood. It's not any more complicated than that.
The trouble with Nixon is that he's a serious politics junkie. He's totally hooked and like any other junkie he's a bummer to have around especially as President.