The main problem with Bully is that, like Crazy Snake said, the campaigning wasn't there for it, nor was the release date so sweet. Bully has actually become one of those 'cult status'-like games. The people I know that own it now got it secondhand, so Rockstar definitely didn't see a penny from those copies. But it's also still such an obscure game, and another part of me also wonders if they're not releasing a sequel, because bullying has become an even hotter topic now than it was when it was released. I mean, look at all the suicides you hear about because these children were bullied. It could be that they have a theme in place for it, but they're not executing it now, because of the extreme sensitivity surrounding the topic of bullying.
I personally would be a bit wary about releasing a game titled 'Bully' when so many teens are killing themselves over in school and social media bullying. It would be industry suicide, no pun intended.