I must admit that response does make it sound like the disc includes an installer for Steam and nothing else. While that sounds (and is) ridiculous, I have seen other games go this route as well.
I don't see it as ridiculous simply because I understand they are insanely busy and their schedule now must be insanely long hours with little to no sleep and that's not even counting the problems they've run into lately. I very much hope they see a lot of success with this game, these guys deserve it.
But the process of pressing the game to disc is handled by a third party manufacturer. It's not the like the developers are cranking out copies of the game on disc in their spare time.
If you're going to put Steam's installer on the disc.. put the game's installer and files there too? Seriously, for a collector's edition of the game not to have the game's installer and files on the disc that comes in the CE box would be pretty lame.