I know what your saying, but part of making something a standard is knowing when to give and take. "IF" it was on all cards, it would be a STANDARD by now, not just a software emulation thing on one and hardware on the other. The old "hook um then charge um" comes to mind. NV should have made it cheap for ATI to include and leveraged that later. Of course I do not know, maybe ATI just would not do it no matter the cost and its all moot, very possible.NVidia alone footed the cost for developing and refining this software (especially if you remember that GPU accelerated physics was an unpopular notion in the beginning), so from a business perspective, why should they help their competitor?
That said, AMD is just as much to blame for not adopting PhysX than NVidia since AMD have proclaimed many times that they "do not support proprietary standards."
If AMD wanted to license PhysX, I'm sure they could do it and then port it to OpenCL. But they lack the will to do it, instead putting their focus on OpenCL's Bullet Physics; which isn't saying much really because Bullet physics is very underdeveloped compared to PhysX.