I don't remember how long ago the physx PPU came out but it's been a hella long time in HW years(like dog years but more).
Ageia didn't want to / couldn't make any next gen cards because it would cannibalize their only customers. No doubt advances could have been made to the PPU's, just wasn't economical or possible in their failing business.
I only hope that nvidia will not be afraid to make a next gen PPU that will be a clean break instead of leaving devs trying to stay compatible with the aged HW. A PPU today should be able to blow the doors off the original with what has been learned as well as just normal engineering and tech advances.
Hopefully they can make a clean break with their first implementation, as sad as it may sound to exisitng owners. I wouldn't want to see devs stuck having to support the old card's requirements when something a magnitude more powerful will be available, yet won't be utilized by devs due to them trying to support legacy HW.
It's like devs still having to support Pentium 4's instead of todays C2d's or quads. NVIDIA's first product would be a great time for a clean break. Then devs won't feel like they have to support equivalent of 6800 GPU's, if they start with a PPU equivalent to an 8800 GPU. Then we won't have to wait 5+ years to see what physics can really do, but 2 or 3 years instead with a clean break and uber fast physics HW.