The Xbox 360 peaked in 2011, what's your point?
I guess Kinect helped.
After the first years a console needs something else to peak like Morpheus or the MS response if they reach the popular market.
I don't think Kinect really helped much:
The launch of the 360S is what kicked the 360 into high gear and it maintained those levels from then on to Q1 2012. The Kinect may have provided a short-term boost, but I doubt millions of people were suddenly buying a 360 just for Kinect. There's never been a case that I'm aware of of an accessory providing such a big boost to sales, not even in the short term. Meanwhile, the launch of new models can often have a similar effect to that of a price cut, providing boosts lasting many months, which we saw the previous year with the PS3 Slim. Europe shows the same thing, with the 360's highest baseline period starting with the 360S and continuing through the end of 2011. Even in Japan the 360S provided a bigger boost than the Kinect, though neither did much of anything to boost long-term sales there.