I'm calling you on this one. It might not be obvious to us right now, but new game genres will continue to sprout up. Touch (included pinch, swipe, etc.) as an input mechanism is new enough that many genres have only come into being in the past few years or so. Games like Osmos and Kosmo Spin are pretty much unique, the latter I just can't imagine working on anything other than touch. People have surely been saying that all genres have been covered in every medium for the last 60 years, yet new ideas keep getting created.