EA is well-known for their sports games. They've always done well since those games are easy to make. They basically duplicate the previous version and fix it up a little bit.
GTA isn't a sports game. It's a huge project that requires time and patience. That's not something EA is well-known for. I've read reports where EA would force some companies to rush certain games. If those games don't come out right or have too many mistakes, then EA will blame that company and that company gets shut down.
A lot of private game companies take their time to ensure that their games don't have mistakes.
