I think that, despite it’s gaming target, the aim in the long term could be more to transform the XBOX into a Digital Media Center for families.
It’s true, in the beginning the selling ratio will be low, but then people will start talking about it, how amazing it is (you can surf your media collection just with waving your hand!) and maybe other people will buy it. To be honest I don’t see Kinect affecting too much the way most current gamers are playing games, but still it’s a wonderful piece of technology.
I’d say give it some time.