I don't know why so many people don't understand why Nvidia disables PhysX with a non-Nvidia card. It's just not profitable to ensure QA. Just because the hack (and in this case the un-locked beta drivers) works for the mayority, that doesn't mean it works for everybody without a single problem (for instance it won't work in Vista). Things that come from companies like Nvidia, Ati,Intel, etc have to work 100% or at least 99.9999999% of the times. Plain and simple.
Someone somewhere will always be able to hack something or mod something that will work 99% of the times without spending excesive time and money on the development, but they are free of responsability if that 1% for which it doesn't work as it should, breaks their PC trying to make it work. Companies have to ensure by law that it works on 100% of the cases and when it fails they have legal responsability. It's that 1% that costs these companies (and this goes for any tech company, game developer, car vendors, whatever) a lot of money in QA, but they have to do it, because even something that seems so small as 1% is a very big number of people in real life, outside iof enthusiast forums. A hack is used by very few people, which can literally translate to 99 people saying how well it works and only one person saying it broke his windows installment. That person will be ignored and people think it works flawlessly which in most cases is probably true, but not always. There's still the fact that it could NOT work in certain cases, because it has not been tested. If something untested was officially released and it didn't work in just 1% of people, that would still make a number of more than 1 million failing cases and that would make a lot of noise... class actions would be put in place etc, etc. I repeat, companies have to ENSURE it works flawlessly and that costs a lot of money, not to mention having access to tech and IP that the company might not have, like for example, for Nvidia Southern Islands/Northerns Islands. How are them supposed to ensure 100% interoperability when those cards are released? Average joe will not understand if for whatever reason PhysX doesn't work in his shiny new card. Why is he supposed to wait 2 months in order to have something he already had working before?
In a sense that's what is good about PC gaming and modding. Someone can make something and you can try it under your responsability. When I say "you", I mean an enthusiast, because average joe will not downlaod it, and that's the difference. Average joe won't download such a hack, but average joe will download an official release, average joe will try such official release and if it doesn't work average joe will blame the company and will go as far as taking legal action, because average joe knows much more about class actions than he knows about tech. And that's all, really. No campany is willing to spend so much money making something work when it won't even work in most systems out there (Vista). try explaining average joe why that something that is official works on XP or 7, but doesn't work on Vista... try...