Yeah I think I agree that while the Kinect device itself was a killer app, Kinect Adventures itself was kind of incidental and not a killer app in and of itself. If say Kinect Sports or Kinectimals had been bundled they would have sold just as well off the back of the hardware's novelty factor.

Forza Horizon 6 is a killer app. Anyone that thinks otherwise is any idiot. Fable should be its next killer app.

Xbox has had a bunch of great games since its glory days, but not many that have single-handedly driven widespread console adoption.

Maybe the one-two punch of Forza Horizon 5 and Halo Infinite in November/December 2021? I recall there was a huge spike in hardware sales around that time.