Brad Pitt sometimes picks good movies, sometimes he doesn't. Sometimes his movies do very well, sometimes they don't. That's pretty much been his career since the start. I don't see any change.
Outside of movies, I could care less. He certainly seems like the type of person I'd never want to hang out with. His commercial is laughably pretentious. But I don't think anyone truly cares enough about that shit to stop seeing his films. I don't.
I personally won't go see World War Z because I think the movie looks like ass, not because I lost interest in Pitt as an actor.