I think you're really misunderstanding how this works. The CPU handles pretty much all game logic. It needs to know the position of each car, enemy, bullet, whatever, so it can decide how to respond to things, if a car hits a player it does damage. As a result it's impossible to hand off such calculations to the GPU, so all GPU accelerated physics do is trivial visual-only effects like cloth and water physics or pieces of paper blowing in the wind. Basically anyone expecting GPU accelerated physics that has logical relevance such as physics based destructible environments is expecting too much. In other words GPU accelerated game logic physics was never the promise of PhysX. PhysX focused on making physics really easy and great from a software standpoint, and that has been an outstanding success.

The visual-only portion of GPU physics is not really that compelling which is why there isn't huge uptake. There would need to be a revolution in how games work on a fundamental level where basic game logic is calculated on the GPU to make true GPU physics happen. We might see that eventually but not anytime soon.