This sounds like a trade, really.
Valve: guys...you really should get your drivers fixed for linux. windows 8 app store starts to seriously compete with steam!
Nvidia: so? Why should we care? The handful of people using linux write their own drivers in assembly just fine. Or so they say.
Valve: we're launching this steamOS thing! And steam machines. You do want to put your graphic card in there, don't you?
Nvidia: well...it's not like we don't want it. But we're indifferent to it. We sell the graphic cards anyway, thanks to all the brainwashing propaganda in AAA-titles.
Valve: and you can still do that on steamOS!
Nvidia: sorry...no deal. Besides...we've got our own handheld we're trying to sell.
Valve: yes...the shield. Which runs on android. Which is based on linux.
Nvidia: erm...possibly. So what?
Valve: ...
Valve: nevermind. How about this: you kick up the driver writing department and we will let you exclusively port half life 2 and portal to your shield. Deal?
Nvidia: deal!