Let's assume, just for giggles, that the percentage of PC gamers that would use Linux if it was a "real option" for gaming is greater than 0. From a business guy's perspective, having your customers switch from Windows to Linux wouldn't really change a thing, but the "no market for Linux games" thing is kind of self-perpetuating as I see it :p
Unfortunately, Linux offers the same features as Windows in most arenas besides gaming, yet people still mostly go with windows for their home or office computer.
To a large extent, Linux is not KISS enough for the average non-geek user (the million of distros out there being the first thing people learn about Linux is not helping... too much choice can be just as harmful as not enough in most circles).
Also, corporations actually like to have a sizable company tied to the OS they are using which they can contact for support.
You don't have to assume, all you actually have to do is to look at HIB sales and the article linked by Mivas at... some point.
Thanks for the pointer.
But the Linux ecosystem lacks heavily in the platform
department, as it was unable to overcome the old unix disease "fragmentation" and to form a platform. Not a good match for distributor who tries to offer a stable, reliable and therefore excellent user experience.
If you try to support Linux with a capital L (considering it one fragmented platform), that is a problem.
However, I think it would be feasible to support a popular subset of the entire Linux ecosystem.
Dependencies, that may or may not be present on the user's system, can be included with the installer as is the case with Windows installers already (I recall one game installing VS 2005 components).
I agree that people re-inventing the wheel in the open source community can be a pain at times. Most of the time, the competing open source technologies are very similar and you'd just like to go with the one that will have the most long term traction, though that is often hard to determine at first.
However, it is worth noting that the private sector is guilty on that front too (ex: the C# and objective-C programming languages... were they really necessary?)... the problems are just shouldered by developers instead of end users (but the end user still gets penalized as it becomes harder for developers to deliver a consistent and platform independent experience). Yes, nobody, but the company who owns the platform can develop official content for their platform so it creates a well integrated experience for the end user (and programmers who want to develop only for that platform), but it gets in the way of developers who just want to create software the works universally across all OSes.
That is a problem for Canonical (as they want a wider adoption of their distro), but from GOG's perspective, that would mostly be a non-issue.
GOG users consider GOG a trusted source, so they don't need GOG games to be added to a trusted repository to trust them (and thus, buy and play them on their Ubuntu distro).