Games with a critical mass of followers will receive better support from open source communities than they ever will from companies.
Try to get Quake 3 support today. Then try to get support for ioquake3.
Alternatively, try to get support for Transport Tycoon. Now try to get support for OpenTTD.
It's not a matter of "game or not game". We have these examples of formerly commercial games for which commercial support no longer exists, but for which open source community support is plentiful.
But the critical mass needed to get that kind of support is in the Quake 3 range... I seriously doubt many games are going to reach that threshold and prove that `à la linux' support can work. Especially on the long term (ie: further along the line than the game launch window).
I am of the opinion that Quake3 is an exception, not the rule.
Try to get Quake 3 support today. Then try to get support for ioquake3.
Alternatively, try to get support for Transport Tycoon. Now try to get support for OpenTTD.
It's not a matter of "game or not game". We have these examples of formerly commercial games for which commercial support no longer exists, but for which open source community support is plentiful.