I'm not really sure Linux gaming beyond certain types is large enough of a community, In most cases Linux is like the bastard of OS's, hardcore even for the hardcore so to speak, I mean at most I see people take abnormally long times setting it up and trouble shooting in which eventually they either give up or finish the setup and never really use the OS. Ideally people do this and say "yeah I use Linux", making themselves appear hardcore.
Honestly in a PC shop I've had many arguments over years with a few people that insist the majority use Linux and MacOS, which if you are including Smartphones and Tablets then sure, but in a Laptop/Desktop environment is not true by any means. Unless there is a severe movement of people to Linux as a major computing platform it won't be really anything more than a novelty experience.
https://www.statista.com/statistics/218089/global-market-share-of-windows-7/
MacOS has grown by about 4.5% but in the end Windows still has a >80% lead in the market, while Linux comes in at a skewed number I'll be generous and say around 4% of the market, It really defeats the purpose of the OS if you have to use emulation in order to cheat running applications from another OS this basically defeats the purpose of picking an ecosystem, buying a product you wish was another product.
Emulation of older consoles and MAME is huge which does inflate the demand for things like the Raspberry Pi, and is less than an Ideal setup process and in general takes way 2 much tinkering time to get running smoothly for the average Joe. PC gaming wise while Valve with Steam is making strides I would say its pretty much the same thing, way to much tinkering just in some cases to make things work. Until Linux gets consumer friendly for the Average Joe it won't become mainstream.
I don't know I would say 4% for an OS that isn't sold by OEMs is pretty good. I somehow doubt 4% of those windows users installed their OS onto a blank drive. Linux has an OEM problem. No doubt.
As for Linux posers ya I supposed that's true, but installing Linux is not hard anymore. It hasn't been for a long time now. Its not a science project. lol Installing Ubuntu or Manjaro on a clean machine is smooth and 10x faster then installing windows. Sure there are more options and people spend a ton of time researching distros... and most of the time they pick what is likely the wrong distro for them. Again OEM problem no doubt. (most people should just install ubuntu or manjaro and be happy... instead so many try to run Cent or some other server distro at home ect)
The major consumer focused distros ARE very user friendly. Average users take to distros like Ubuntu or Manajaro with zero issue. They are more familiar to them these days then current versions of windows are if they are coming from 7. I have set plenty of people and offices up on Linux... Chrome/Firefox Libre office/MS office 365 VLC.. spotifty ect all their everyday stuff is there and it all runs very smoothly. The days of new users being required to hit up the terminal for every little thing are long gone. Sure Linux users will still suggest CLI to take care of tons of stuff... and windows users balking at that is just silly, even MS themselves suggest using command / powershell to do a bunch of stuff in windows. Its the easiest fastest most universal way of taking care of many things.
What is required to increase Linux marketshare is actual shipping Linux machines. Most people shouldn't be installing operating systems. Even though Linux and Windows are both easier to install then they where 10 years ago, most people don't understand how things work well enough. Outside of Dell developer machines there aren't really any major well known OEMs shipping Linux, I don't know what it would take to change that. I would imagine it would take a MS move so unpopular with companies like HP and Lenovo for them to rally behind one of the major distros.