Because of the limitations of ones gaming area and Kinect. Like I said above, you can't play any 'hardcore' games (like FPS, Action/Adventure games) solely with Kinect. You can't move forward very far because you're going to either be out of Kinect range or walk into the TV. What's the Kinect camera's area? 8 ft or something like that? That's how far you can move. Unless the game is on rails and it moves for you, which takes away any real hardcore aspect. Now if the game is on rails and using a FPS example, how are you going to reload? Sure you can shoot by using your fingers like you did when you played cowboys and indians when you were 8 years old, but reload? Waggle your finger I suppose? How will Kinect determine the strength of your throws if you want to throw a grenade? How will you be able to select a grenade? Or changes weapons? Now moving on from FPS to action game, something like Uncharted (just as an example), again, a lot of area to explore in the game, how will you do it in the game? How will you jump up to ledges or across large gaps? Same goes for a game like Mario. I mentioned Kinect might be used well in compliment to the controller but there are too many limitations with Kinect to ever be used solely in hardcore games and that is why it will not get much more better than it is.