Even with the Kinect, Microsoft can't push another console of even remotely analogous design. When any developer can make decently pretty games with an open-world and still have ridiculous draw distances, there is just no way to push hardware with the "but it's more powerful" mindset. They're already having trouble with that this generation.
Really, it entirely depends on what technologies get developed in the future. There's a youtube video of a scanner actually reading a video playback from someone's brain. http://gizmodo.com/5843117/scientists-reconstruct-video-clips-from-brain-activity Granted it's terrible quality, but this is the beginnings of a completely immerse virtual reality environment (The Matrix, .hack, Sword Art Online, that kind of thing).
It's entirely possible Gen 9 will be the VR suite generation. They've still got ten years for R&D. THAT will be the last generation.
