Ah well, I'll take the totally minor hit for the ease of use, huge application library, and compatibility that Windows 7 offers.
1)I find this classic gamer statement so extremely ironic.
Take it out of context, put it into the mouth of a Mac user and you get:
"I'll take the hit in performance for ease of use, growing application library, and compatibility OS X offers."
2)I came across this sentiment on another site, and I think it's worth repeating:
Most gamers are not highly tech-literate (the small minority of people who post here, and at other 'enthusiast' sites
are not 'most'); the most telling support for that is the continued success of companies that purposefully market prebuilt systems to 'gamers', with over the top, angular, transformer-esque aesthetic ads that are geared towards said juvenile 'gamers'. Those people won't want to switch to Linux proper. But, if Windows 8 is so amazingly horrible, it's very possible that a Linux powered box with simplistic UI could be marketed for the vast majority of simpleton users to play games on, as well as simple PC tasks. Steam box anyone? IIRC there's already a simplified gamer version of Linux out there.
3)Taking into account what I said in #2, it would be wrong to base an opinion on how much anyone has spent on Windows based games through Steam. That's a personal problem, and not one that would really concern Valve. If you've bought a game, they've got their cut of the money and so does the developer; they don't care
much after that, beyond making the occasional patch.
4)A slow migration to Linux is doable. Valve can port their games and forge the path for the other developers to follow whenever they feel comfortable. As soon as the selection of games becomes enticing, more and more users will make the move. Leaving the brainless techtards gaming on Windows 8, and the stubborn, older users, who still have access to Win 7 gaming on Win 7. I have no doubt something along these lines has occurred to the Valvians.
5)John Carmack's comments about how in his experience Linux users don't want to pay for games doesn't apply to a situation like that in #4. If as a Linux user you have the choice of playing an open source game that doesn't have much support, that is buggy and constantly in development OR playing something a little more polished and ready for primetime, coded by professional game developers, and that everyone else is playing... well the choice is simple for most people. Right now Linux users are not primarily gamers and make up a small percentage of the market. If you have a large number of former PC users make the move to some flavour of Linux that is easier to use (like Ubuntu)... BAM! The whole game marketing situation changes drastically.
It might not ultimately be something that the open source movement would like to see, as it might have some future commercial implications for Linux they would rebel against, but money flows where the user goes.