The main thing holding back is porting of those games to Linux, which doesn't have DirectX and will never have it. Secondly, there's not such a high user base for Linux compared to windows and out of those most people aren't the ones who really like playing games and all. So, it's a vicious cycle.
But, AFAIK there are a few game, too few to make a major impact.
I believe that there will be eventually latest and greatest games for linux too but it will surely take some time as the momentum is clearly towards Windows right now.