What a completely fail-tastic comment - from someone who should know what they are talking about!
I challenge Mr Carmack!! How to do you measure the popularity of your Linux ports - when you can't buy a Linux-only version of the games!! 
It's a circular argument...
Wine will never replace native gaming...
1) It runs in user space - low FPS and frequent stuttering (read "pause") is unacceptable to any gamer
2) Instability - simply put games can crash Wine (my current experience with BMS, look at Crysis - needs a patch just to run)
2) To many modern games have sophisticated DRM/online checks that will never be fixed (e.g. Punkbuster, etc.)
3) Wine updates maybe a problem - but even more problematical can be updates to the games themselves!
Don't get me wrong I do my bit to support the Wine project... It's lovely to see games like S.T.A.L.K.E.R. running on top of ARCH, etc. - but you need an order of magnitude faster system (
i.e. at least 2 Nvidia GPU generations), than Windows 7 would need, just to run the games at the same FPS.
Has Mr Carmack actually spent any time using any FPS games on Wine?? Me thinks not...