This is a clear example of management not getting an idea. Years ago Microsoft Research was doing a load of camera research and when the XBox Vision Camera was leaked I got all exsighted and wrote a post called Two Cameras Not One for the XBox360 where I talked about the stuff that Research was working on. I was excited because I seen the potential of what they where showing and how that could be worked into gaming. The videos in that post have all been taken down and the best I could find was a small image of GWindows Here, but what they where showing in 2005 was components of what Natal is.
I know that they could have done Natal in 2005, but didn't and I suspect the cause of this was short sighted management, as soon as the Wii was proven to print money, Microsoft called up Research and they made Natal.
This makes me annoyed because I know of a dozen other cool technologies that MS Research has that I know now will never see the light of day until some other company blazes the way forward and creates a market for it. And then when Microsoft responds everybody calls it a Me-Too! move from Microsoft and Research doesn't get any credit for their work outside of a black cube on their windowsill (they get one of these everytime they file a patent).