There is quite big market for non-seated entertainment - Wii, Kinect, etc have shown that. It is a very different market from the people who currently have high-end gaming PCs suitable for VR, but the number of people who like and want full-room experiences is quite large.
Maybe I am completely missing some niche where Wii and Kinect are celebrating long term success, but my current impression is that they are more examples for short term novelty success than for a strong long term development. Better than dance dance revolution mats, but only marginally.
