How is Kinect a success exactly? It's not pushing HW anywhere past normal or is it pushing sales of SW. If anything it will be Kinect holding back sales of the 360 this year due to M$ focussing entirely on the new user experience. You can expect the majority of SW sales to be 3rd party for 2011 as there is nothing really of value coming to the 360 from M$ for their core audience.
Xbox has never been above a million... it was this holiday... twice... I don't think that was a coincidence. MS have got people buzzing about the Kinect (in australia at least). Out of all possible outcomes, Kinect slowing sales does not come to mind unfortunately. MS is still making games, MS is still getting exclusives, as shown as the same press conference where they unveiled the new xbox and showed Kinect and when it was released at E3, Codename: Kingdoms was announced. Xbox getting COD map packs first.
MS aint forgetting the "hardcore" section, they are just focusing on the "casuals" as well now. I myself and a "Mediumcore" as I like both sections :)