Game developers could do lots of things to support Linux, but many prior attempts to support Linux gaming have shown game developers that it's generally not worth it from a resources perspective unless the engine you're using already supports Linux and you don't need to do additional work to get your gaming running on Linux.
Ideally this is how it would be. Develop the game targeting Windows, and simply don’t do the things that unportably tie it to Windows. If you develop it from the start as cross platform, then it shouldn’t be some gargantuan effort to port it. It shouldn’t take that much longer to use platform-neutral APIs than the Windows-only equivalents.
Then just fling off a “totally unsupported Linux build”, stick it on an FTP server, ignore support tickets mentioning Linux, and let the Linux people figure out how to get it working—they will! Let them figure out their driver problems or which distributions ship the right library dependencies. A totally unsupported build is at least better for Linux users than abandoning the platform entirely.
I think a lot of games fail to work on Linux not because of the support costs or the platform fragmentation, but because the developers just don’t care or they choose engines and technologies that are not cross platform. It just never crosses their mind to do it differently.
Now, same thing happened with one of the worms games, Team17 was dismissive and rude. I ended up just getting a refund. I've been a fan of the series since the very first one, i've bought a bunch of their games over various systems, I own a copy of worms 3d on both GameCube and ps2, but I don't plan on buying another worms game or anything else they put out any more.
Also most game devs don't have Linux machines to build or test the game on in the first place.
I thought about it once, tried installing Ubuntu-- it wasn't as simple as I'd like, but eventually worked.. except it didn't seem to be aware of the GPU and was running at 640x480 or some shit.. deleted it.