"It is exactly the same as Windows 7 in same time after launch."
This would be a valid comparison, if Windows 7 had been sold for 30 bucks in the first two months, too. But it wasn't. It was sold at full price, except for a very short (a couple of hours), very limited sale (couple thousand licenses) on Amazon, I think.
Game-devs and publishers aren't forced to use Steam's CEG. Many games are using it just like a repository, i.e. you can copy the game-folder out of the Steam-folder and uninstall Steam, and the game will still work.