gooberking: You really don't need to do a lot of research to find out that peppering your code with dependencies on MS only libraries isn't going to make cross platform goals easily attainable. And if someone thinks it's takes magic, super powers to accomplish, then maybe people need a demystification message and not one about how only ubber geeks can understand it - not lowly game developers...
...One of the biggest mistakes someone can make is doing something in Windows and thinking they will just try to figure it out after the fact. After the fact often has one making lots of little mistakes out of ignorance that are hard to undo. Oddly one can develop for Linux first and it will generally work for Windows with less fuss than if one starts from Windows.
...and I think we saw this first hand with the long-promised and still-somewhat-broken port of Vessel from HIB 6. IIRC, the Linux/Mac port was originally seen as being a trivial effort, but one of the major problems was porting from Direct3D to OpenGL. I think there were some issues from the game also using XNA/.NET too. I do remember reading on the port dev's Twitter that the game was left in a very broken state, and that it would likely never be fixed to the degree that it should have been.
With respect to the subject at hand, I've been very disappointed with their lack of progress on their attitudes towards Linux users. I wouldn't necessarily suggest actions like amok's
infamous thread promoting Steam/Humble Bundle. However, I think that it would take something like a concerted refusal of purchasing from GOG on the part of Linux users, or more visible pressure from other corners of the Internet., to effect some change within GOG's management. I still think that Linux support will eventually come to GOG, but the longer they wait, the more they will lose out on the goodwill of the Linux community.