PhysX isn't going anywhere because nvidia boxed themselves into a corner. No developer is going to innovate with a proprietary technology that will only work on half the hardware of a small market (PC<<consoles). Nvidia doesn't seem to have the pull to do anything with it despite owning the technology for years now. The fact that they have to turn off physics and then use overblown implementations to try to market their product just shows how lacking of innovation and quality the product really is.
This really isn't an AMD vs. nvidia thing; just because people point out nvidia's failings doesn't mean they're automatically for AMD (I know that doesn't fit in with fanboy logic, but bear with me). But if people want to bring it up, TressFX is AMD's attempt and they got two things right A) it's open (any card can use it); B) it adds an effect we don't have but really need for modern games (dynamic hair). What's done with it and how it's adopted will be interesting to see.