The success of Kinect (at least in regards to their relationship to 360 success) is hugely overrated. Sure the peripherals themselves sold a lot at first, but I think a lot of that were current 360 owners. The fad has dropped off quickly since then. You can now buy a used Kinect on amazon with Kinect Adventures for $54.
I don't know anyone who got a 360 just for Kinect and I don't think too many did. I think much of 360's resurgence around 2010 was mostly thanks to Halo 3, the explosion of the Call of Duty franchise, the console redesign, and price drop.
At the end of the day, games are what sell hardware, and this includes peripherals like Kinect, and to say this peripheral has a weak lineup of games is a huge understatement. What exactly are all these stellar kinect games that sold 360s?
