IMHO, Linux users are lucky to have any support from for-profit companies such as nVidia. I imagine that it is quite costly for them to port something as complicated as a highly optimised, multihardware driver to a totally different platform.
Having said that, I was disappointed when I had to sell on my brand new GeForce 2MX because I couldn't get the nVidia drivers to work GLX with it. However, I have since been using the same drivers with a GeForce 2 at work and a GeForce 3 at home. Both computers are now stable - the uptime of the computer at work in now well over 200 days.
Also, I can understand nVidia wanting to keep their drivers a closely guarded secret and, therefore, not releasing them as open-source. Hell, I have to think hard before giving my source away and my code is much simpler.
So... thanks for all the work you've done, nVidia, and keep it up!