I believe that consoles sell first and foremost because of first-party exclusives. Obviously, with Xbox, third-party titles become extremely important as well. For just starting out though, debuting a game platform, you have to have content to differentiate your console, otherwise it doesn't appeal to anyone.
So, my question is, without something like a Steam-exclusive Half Life 3 as a launch title, how are these products going to do in the market? Are any retailers going to want to carry them?