Well the dedicated PsyX processor is one of the reason why the NVidia PnysX is going to loose to Havok Physics.
The other reason is, it is NV proprietary technology. Does NVIDIA think that AMD and Intel is going help sell more NV hardware?
Anyway this article says it better than I can.
The Inevitable Bleak Outcome of NVIDIA's CUDA + PhysX Strategy
Tuesday, May 12, 2009
There is another on going pool at TechPowerUp
about buying decision and it doesn't even address the question about the need for buying a "dedicated PhysX processor". I think if it was pointed out the numbers would be even lower.
There are many more Titles that use Havok Products
and more Upcoming Releases
And lastly it looks like AMD and Intel will unite against NVIDIA PhysX