What if someone installs a self-made Linux distribution on their self-built toy car? How could GOG support that? Linux is just too dangerous, man, I hear you can install it on a computer and then unplug the monitor and still have it stay on the computer. Someone might do that and complain that he can't play now on his system, and you can't very well tell your customers to plug the damn monitor back in or buy one if they don't have one.
Hahaahaa, that's a good one. Some humour is always appreciated. My router runs Linux but I would not expect it to run games. 8MB of RAM might be enough for it, but it cannot even run Zork because it has a different hardware architecture. i686 Linux might be a better restriction. Apart from that, hardware requirements are listed with some games.
Don't be so sure of that. Valve supporting Linux on Steam also raised quite a few eyebrows...Remember?
Besides, the company that managed to publish System Shock 2 has had bigger hurdles to contend with.
I think it is only a matter of time, especially since the MacOSX and the Linux platform belong to the same (if distant ) family. Just look at the Humble Bundle sales...