I won't go digging up the quote but I remember posting before Kinect and Move's launch that NO game released for the peripherals would sell a million (Of course, I was wrong)5 based on the simple fact that Kinect/Move games are only available to a fraction of the 360/PS3 audience but they are competing against every single 360/PS3 game.
Just because I own Kinect doesn't mean I have to choose between The Gunstringer and Dance Central 2. It means that I have to choose between The Gunstringer, Dance Central 2, Gears of War 3, and Batman Arkham Asylum! As a result, it'S a handicap situation as far as sales go. With that in mind, I think Kinect software is doing well--especially when most of the games are less than two gigs (I install everything) and have simple graphics.