PhysX is not meant to be widely used. It's meant to be a bulletpoint. It's a hypothetical advantage and you'll pry that from nVidia's cold, green dead hands.
They use it as a way to differentiate products they've helped develop and market from products they didn't have anything to do with.
If they wanted it to be widely used, they'd have given it a better CPU-based variant at the very least. You know, adding this thing called multithreading to it long, long ago. Or even redone it by now to be based around DirectCompute but with marketing speak!
No, friends, PhysX is meant to be like Truform. Only those that are paid to use it will use it and everyone else will ignore it exists.
I own a Geforce 670 and even I can't wait until DirectCompute is used more universally. I'm hoping it happens with this coming generation of console ports. Hell, I live in hope that developers will develop their games for PC first since it's the most generic device of all the "next gen" and then they'll make the few minor modifications to port to the new Xbox and new PS4 since those devices are now so close to PC's.
Especially when the platform they're developing these games on is PC's anyway. Wouldn't it be easier to just build the game for the PC you're already using, the cheaper device to maintain, and then use the Xbox and PS development kits after you've got the game mostly done?
I'm hoping that kicks PC gaming into overdrive. And yes, I'm hoping this leads to including DirectCompute that actually impacts gaming instead of, "Wow, look at that cloth flap!" or "Wow, her hair has so many split ends!"