They're selling in spite of (and now because of) folks like me.
Yep, I was one of those haters when the service came out, but I'm a Steam convert. There's just too much to like. Crazy low prices during sales + the almost instant gratification factor = lots of impulse buys. I find myself visiting the steampowered.com site to check out the current deals.

Sure, you won't be lending out discs anymore, but you won't be losing/damaging them either. OTOH, you get easy access to your old games for as long as Steam sticks around (the only possible catch, I suppose).

I'd never played the Mass Effect series before, then saw them on sale on Steam. Picked up ME1 for 5 bucks! (ME2 is currently $24.) That's a LOT of entertainment per $.

Don't hold your breath. Although the Federal Desktop Core Config (FDCC) only mandates *security settings* for federal gov't XP/Vista machines, many IT PHBs have taken it as a mandate to USE Windows for the desktop environment. Hard to blame them, if you just go by the title of the program. I mean, where's the Linux FDCC, or the Mac version? Oh, that's right... they don't exist (yet).

Add to that the fact that AD, Exchange, SharePoint, OCS (among others) are de-facto standards across the DoD, and you can see where that leaves us for desktop machines. Not impossible to integrate alternative OS's, just very difficult; and nearly impossible to reap all those "MS-unique features" from your Windows servers w/out Windows/IE/Outlook/OCS on the other end.

I think it's safe to say that vendor lock-in has been achieved.