Going back to the OP's post, the truth is, Linux is *at the moment* NOT as gaming centric as Windows and one should not use Linux expecting it to completely replace windows as a gaming platform yet.
However, with Valve's involvement, and more and more developers now making games available for Linux as well as Microsoft insisting on making Windows more and more irritating to use not to mention costly if they had their way with a yearly subscription model for both Windows and office suites, Linux never looked better as an alternative.
From my perspective, the different distros and Linux DE variants in general reminds me of the hayday of PC computing. As then as is now, we have different DEs / OSes vying for consumer support and while some platforms such as the Amiga were in my opinion better for gaming / multimedia, what it really comes down to is numbers of users / cost of using said platform. A little thing called DOS came along and even though many other platforms were superior, DOS became the defacto platform developers developed for, simply because it was the most used. (Piracy helped of course but Bill Gates and Co. would never admit to that fact.
)
So now from my perspective, I see a similar event playing out.
Windows had been the king of the hill in gaming simply because there was no one else, because no AAA title dev would even consider to develop a game for Linux.
Valve and crowd-sourcing / crowd-funding portals such as Kickstarter is changing that however.
My own motivation for jumping back into Linux space is due to Valve and certain games that I backed on Kickstarter, Namely Pillars of Eternity, Star Citizen and Tides of Numenera. All had backers asking for Linux support as part of a milestone event or right off the bat, reason for their contribution. Star Citizen recently hit over $35 million in funding and with linux support planned.
That is a clear message to anyone that Linux isn't "just meant for servers" anymore.
With Valve's choice to use Ubuntu though, I see the PC gaming sphere shift even further and perhaps solidifying Debian (and its forks) as the "goto" linux as opposed to Slackware and Redhat (and their forks).
As it was back during DOS days, its all down to numbers and I am pretty sure I am not the only PC Gamer to be suddenly interested (or in my case, rekindled interest) with Linux and we will see an influx of new users looking to see which linux will do the job as a gaming platform.
At the moment, I feel that Debian and its variants stand the most to benefit.