BethSoft has a bigger audience audience now, thanks to the X-Box sales of Morrowind -- yup, the console audience. It only helped propel them into developing their PC RPG's onto also more consoles, such as Oblivion and Fallout 3 -- both on X360 and PS3. So, it's kind of no surprise they are in bed with Microsoft for FO3 DLC on the PC exclusive over G4WL.
I don't really like that M$ and BethSoft are in bed, though -- since G4WL will be the only place to get the damn DLC, which could mean BethSoft and M$ could charge whatever they want for the DLC and have you by the balls for that cost b/c they're the only ones in town to have it; Bleh! I'd rather have more options on where to get it.
I really don't mind playing FO3 over G4WL -- since you can also play the SP-based game without even connecting to the Net and without connecting G4WL at all. At least with G4WL, I have that option to use it or not use it. If you want to play a Steam game -- even if it's a SP-based game -- well, you actually got to activate the game first and then you have to run freakin' Steam.
Ah, yes -- the new G4WL is much better than the old one. I like the new toolbar, actually. At least now, I ain't gotta hop through many menus just to see my Achievement points.