The problem is how much they're losing with each console sold. Yes, they have services to sell to make up the costs, but MS' goal should be to mitigate the cost of the console to turn the red into black. Not only that, you have to factor in the R&D costs of developing the console, as well as writing off the R&D (and probably supplies) of the Kinect.
EDIT: I also forgot to mention packaging/distribution costs. Even if the cost of the parts to construct the console is under the MSRP, getting the finished product to the store will put it back in the red.