For example while Metro Last Light is going to be ported to Linux, it will be tied to Steam for no apparent reason (it doesn't strictly depend on any Steam lock-in features). I.e. it's the common urge for DRM that drives this.
http://www.forbes.com/sites/jasonevangelho/2013/09/10/metro-...
Why I mentioned GOG - it's the only major distributor now who can seriously compete with Steam. And they have a clear DRM free stance unlike the later.
As for GOG, they didn't say that they don't want to support Linux. They clearly said they want to, but the way they planned it for themselves makes it complex and takes long time to research/develop. While we can disagree with GOG's approach, it's up to them to decide how to enable it. So let's wait and see what they come up with next year.
Humble Bundle didn't reach the scope of GOG yet, plus they don't even have a strict DRM free approach unfortunately. On the other hand they work on real DRM free Linux ports and they always mark which games are DRMed and which are DRM free.
To grade the situation, I'd give Steam very bad, and HB - average mark (DRM wise).
GOG has more resources to be disruptive while being completely DRM free, and to take on Steam in a serious way.
Seriously the position from GOG is plain BS. If they really wanted to support Linux, they could easily package most of their old games with Dosbox and 90% of them would run fine this way. This is the large majority of their current catalog. And I have a very hard time to believe it would be difficult to support a few key distributions. Or they could take the approach "we support only Ubuntu officially" just like Valve does, and let the Community support other distributions.
So, as much as I love what GOG does, their position regarding Linux was a great disappointment. Especially coming from a developer from Eastern Europe, where Linux is clearly stronger than in other PC markets around the world. I don't see CD project porting Witcher 2 to Linux either, and they haven't made any announcement in that direction for the upcoming Witcher 3 either.
Supporting "Non-DRM" software while running on a DRM friendly environment (Windows/Mac) is a very strange place to be, honestly. I expected way more from GOG.
This was not about DosBox games which are already playable. It was about starting support for native Linux games which is not trivial. In general I agree with you that their approach of "all or nothing" in finding a way for long term support of native games is far from perfect, but what can you do - it's their business how to do it. They listened to feedback but didn't go the iterative way.