Totally uniformed and inexperienced with regards to Linux, as I only recently started messing with it so as to self-teach myself on it's use...so take the following with a huge grain of salt...
If I was a Linux user/gamer....I am not sure how I would feel about the concept of Linux becoming a domain of the mainstream. The mainstream taking up gaming as a hobby has not really been something I have looked at fondly. The mainstream brings "big money" and "big money" brings a bunch of suits, publicly owned companies, and the next thing you know...the games are made by people who don't know or care about the product itself...only if it makes them a profit.
What is the Linux world like 10 years from now if the corporate world starts controlling it's development direction? I mean, gaming is a business...and I am not so naive as to even begin to claim otherwise...but there is small business and then there is the corporate world, and the decisions they each make with regards to their customers and their products are very very different.
Not that any of that is completely on topic..just kind of thinking out loud.