PandaLiang: Because Skyrim was the first game Bethesda went Steam only and most of the subsequent games followed used steam as drm, plus it has deep integration to the steam workshop. However, I will be very exciting to see it coming to GOG, as it will signal a change of direction and it shows that Bethesda is willing to experiment drm-free on their newer games.
If we're talking about games they developed then, yes, Skyrim was indeed the first game they went Steam-only. If we're talking about the first game they published, then that honour goes to Fallout: New Vegas, which was released one year before Skyrim.
As for the integration thing, it also won't stop a release here, just like it hasn't stopped other Steam workshop-integrated workshop games from coming here like Dying Light, Kerbal Space Program, Mount & Blade: Warband, Prison Architect and Trine 2.
karnak1: I may be mistaken but I think
New Vegas was Steam-only since day one. At least I remember that I decided not to buy it at retail because I saw the Steam logo on the back cover.
No, you're not mistaken.
karnak1: Besides people should stop make assumptions about what games GOG can or cannot get here. Back in 2013 I remember reading tons of posts here where people were stating that it would be impossible for GOG to land
VTM-Bloodlines here.
Sssshhhhhh... (it's all a form of reverse psychology).