APB has a really bad marketing compared to other games, and what happened on it's release killed it for good.
Real Times World gave ppl a lot of hype, APB was going to be GTA online at that time, but it came out mediocre and just a month later they went bankruptcy.
Yeah, APB had/has potential, it's just bad luck that they never knew how to develop it, not to talk about the never-ending milking by G1 since they got the game.