Linux would be hurt more by nVidia's absence than nVidia would be hurt by Linux's absence.
Linux could disappear tomorrow, and there are plenty of free Unix-like alternatives that easily fill the void.
If nVidia disappeared tomorrow, there are lots of Linux contracts that would simply stop (and most likely switch to Windows).
Now, you can argue ideologically, but part of the reason why Linux is popular stems from the fact that Linus was more pragmatic about licensing rather than RMS' dogmatism.
If you want to see what a world with a strictly enforced GPL without modules looks like, look at the device support for OpenBSD. A lot of Linux folks would be very upset being limited to that set of peripherals.