You’re absolutely right that Steam is about trying to turn your PC into a console. The problem that Valve is facing is that there no intrinsic reason a PC needs Steam. There’s no intrinsic reason a gamer needs to use it, and there’s no intrinsic reason a developer has to go through them. By contrast, if you buy a Wii, you have no choice but to buy games that go through Nintendo’s approval, and a developer must get its games approved by them. In that light, what choice does Valve have other than offering bajillions of games at fire sale prices? I don’t really see how it’s a sustainable business model, because as games like Battlefield 3 and Diablo 3 show, you don’t need their backing to have a successful major release. Once they hit the bottom of the barrel with their clearance-style sales, what next?  The only real advantage they have is that they can advertise things to people effectively–if you’re running Steam, Valve is advertising to you. GoG can’t really reach you with ads unless you go to their website. 

GoG definitely advertises. I see their ads all the time at certain gaming sites I go to. These ads are lasering these certain sites because they know they are the type of customer who is interested in ‘Good Old Games’.

GoG has said they wish to become the alternative to Steam. We’ll see how that goes. More competition is good.

Aside from sales, Steam seems to focus on ‘Steam achievements’ (WTF? Why?) and is now trying to get more ‘user generated content’. I expect it to be as successful as the ‘User Moderated Steam forums’ which are a menace to mankind.

One could make the argument that the existence of Steam is delaying PC video games from adopting a DRM free solution. Because of this, Steam is the enemy to the gamer, not the friend.