The main problem with this delay are releases that don't provide Linux versions on GOG, while do it elsewhere, because developers can't or don't want to go extra length to make Galaxy optional, and lack of Linux Galaxy libraries makes them cancel GOG Linux release altogether.
Wait, I don't get this part. How can Galaxy NOT be optional for titles with single-player content? Has something changed about Galaxy being totally optional unless the game uses it for multiplayer?
And if Galaxy IS optional then it's 100% the fault of developers if they don't want to release their Linux games here because there is no Galaxy for Linux.
Linux is low on GOG's priority list, which is quite understandable. They have their hands full with the Windows version, which is still far from bug-free and still has a lot of room for improvements if they want it to compete with Steam. Unless there's something I'm missing here, I wouldn't say that it's GOG's fault that developers think it's not worth to release their Linux versions here if they can't use Galaxy.