Actually did the math on the trends here, and naively extrapolating it seems that the year of Linux on the desktop is around 2050. In the meantime we have Steam, AAA games and 1.16% market share now, according to Steam Hardware Survey. That's a third of what OSX does!
Actually that's fairly impressive and a great sign, but I suspect most Mac users get their games from the Mac App store while Linux gamers are more likely to know steam even exists. So I doubt it tells us very much about the actual number of games and gamers on Mac Vs Linux.
WARNING: Do not touch the repo until you've had more coffee ;)