I wouldn't worry about it. I wouldn't surprised if Microsoft supplied a new physics module for Directx which allowed physics processing using none proprietary methods, much the same way Direct3D offered an alternative to 3dfx. It won't be here tomorrow, but if this ATI problem goes critical among gamers MS will step in.
Lets make note that no developers are required to use Physx, so its not right to accuse Nvidia of being unfair. Nvidia offers a feature that developers like, so they develop for it. Nvidia was smart enough to see potential in the technology. Instead of hating on Nvidia, we should be saying well done and then look toward ATI to see if they can come up with an alternative, and if they can't, then so be it. Thats how competition works. Basically, at this point ATI needs to put up or shut up.
I'm not pro Nvidia or ATI. I've bought various cards from both companies over the years, and will continue to buy whatever is best at the time. I would have never thought that a physics engine would have been a dividing factor, but thats where the line is, like it or not. In the mean time, if your pro ATI and don't like the situation, your only recourse is to not buy games that use Physx in the hope that developers will choose not to include it, or to make it optional. At the moment, developers prefer to support Physx. Well done Nvidia