Had they contacted NVIDIA and ATI 6 months ago, I wonder if these problems would be here now.
Knowing how closely Carmack has worked with GPU vendors in years past, I would be extremely surprised if either nVidia or ATI had not been informed several months prior about driver issues affecting Rage. My guess is that nVidia and ATI had plenty of advance but were slow to deliver fixes, and id was forced to decide whether Rage should be released on schedule - hoping that driver updates would be available by launch date.
All of the above is pure speculation, but I know Carmack has mentioned working closely with both vendors in the past to address driver issues.