HunterZ: What really confuses me is why all of the DOS games on GOG aren't available on all 3 OSes (Windows, Mac, Linux) since DOSBox ports exist for all of them, and since GOG has already figured out how to produce versions of some DOSBox-bundled games for all 3 OSes. I wonder if it's just laziness on the publishers' part, as GOG probably wants an up-front fee to produce the installers.
I ported X-Com that was already on the Dos-box for Windows (only needed sound tweaks in the Dosbox configuration file and some third party sound library) some time back in like an hour so yeah, technically difficulty is probably not the bottleneck.
I guess you can only get companies to bend over so much for an OS that has 2% of usage share (probably more on GOG, but once you include the entire market, I'd say 2% and I doubt they'd bother with a Linux port just for GOG).
It's up to people to use Linux (because it is free-er both ways) more though I get it:
1) They all grew up using Windows and most people are not computer people: They don't want to re-learn what they already know with a new OS. Technically, they should have to fork 100$-200$ every couple of years for Windows (which is still better than learning something new for most), but the cost is concealed by the that fact that most computers sold come bundled with Windows.
2) iTunes, most games, Netflix until recently (now runs directly in Chrome) and a bunch of other higher profile proprietary software won't run on Linux. Part of it is the low adoption, but I think it is also the fact that they don't want their DRM running on an open-source OS that won't be able to provide strong guarantees for DRM below userland (yeah, technically, people will crack Windows for that too if needed, they are just fewer in numbers).