PhysX becoming part of the DX12 spec? That's highly, highly unlikely. Nvidia has quite the opposite corporate policy vs. AMD, they believe in proprietary "only us" features to help differentiate their products. AMD is much more apt to create, use and adopt open source initiates, for better or for worse. It would be nice to see something like PhysX become part of the DX spec, it would benefit all of us. But then Nvidia would lose a checkbox feature that they are definitely keen on.
And I think we should wait for Cayman before we declare Nvidia the "king" of tessellation land, not to mention tessellation on Fermi only shows a great advantage on synthetic benchmarks (especially ones that are sanctioned by Nvidia). BTW, for all we know, PhysX could be made to run better on AMD GPUs, we simply don't know because it obviously not coded to talk to Radeon hardware.
But as usual, being first with technology is in no way, shape or form a guarantee of success, nor does it necessarily help you keep the technology leadership. There are hundreds of such examples.
edit - I would like to add that 1)Nvidia is apparently stronger in tessellation but it comes at a cost, obviously. Nvidia is getting far worse performance/die size vs. AMD, there are always trade offs. 2)It has yet to be determined if Fermi is able to show higher tessellation performance when the GPU is called on to do other parallel tasks. In other words, it really depends on the game and how it is designed and coded to take advantage of the hardware. Why do you think Nvidia (and AMD) are so keen to have developers use their coding techniques? Obviously they both want the games to play to their strengths.