It would require work to disentangle the game from Steam, which is enough of an excuse for bethsoft to not do it.

DRM free was enough of an excuse not to sell games on GOG too ;)

That's simply not true though. Plenty of games, both from AAA devs and indie ones, have used Steamworks and then gotten DRM-free releases. I don't think it takes that much work, and if an indie developer can afford to remove Steamworks, then Bethesda can certainly afford it.

In any case, developers and publishers don't need an excuse to not release games DRM-free. For most, if not all, it will come down to money. When releasing Skyrim on GOG is clearly more profitable than not doing so, we'll see it here.

Erm no. It's really not hard, I'm even willing to bet that GOG did all the work for the Steam games that are already here... not the publisher since GOG is known to remove DRM. All you got to do it modify a few files and include the steam_api.dll file and essentially trick the game into thinking Steam is installed when it's not. For instance if your remove said file from the GOG version of Saints Row 3, it will fail to run because it thinks Steam is missing even though you have the GOG version. Because all the GOG version is, is the Steam version with naturalized DRM.

It's why Steam games are pretty easy to crack...