kinect sports: 1.08M
your shape: 210k
kinectimals: 320k
dance central: 600k
those are the only 4 "good" games and i dont think the sells are too bad. they all will have very good legs and i think the development was very cheap.
sure the other games sell very poorly but they are so bad why should they sell a lot with 4m kinect at the moment? look at the sales from games like castlevania: lords of shadows which is a very decent game and has 45m 360 owners as possible costumers and you will know that the kinect sales arent bad.