I think his point is that if the nvidia company felt threatened by Linux, then they would immediately stop producing for Linux. In which case the Linux ecosystem would shrink, and the platform would become less useful.
Would this actually happen? Would it effect Linuxes popularity? That's harder to predict.
Are they really flouting the GPL though? I think you could make a better case that SteamOS is, with an integrated Nvidia driver.
What makes this different IMO from VMWare is that they are not creating a work that exists purely b/c of Linux, instead they a making a piece of software that allows their hardware to work with a Linux based machine.
I think those are two very different types GPL violation. One really does flout the GPL and exploit Linux kernel devs, the other I think is generally viewed as an enhancement to Linux, thus less interest in fighting it.
They're flouting the GPL in the sense that they produced a binary-only driver enabled by a compatibility layer released under GPL that, in my uninformed opinion, probably violates the GPL. It still doesn't do me any good, though; I'm on my second laptop with Optimus graphics, and they're just not going to make their hardware work on this machine when it's not running Windows. Fortunately, I only need 3D acceleration when I'm gaming, and the machine came with a Windows license, so dual-booting is an option for me.
Would this actually happen? Would it effect Linuxes popularity? That's harder to predict.