Look at this amazing demo of silliness. I love Peceptive Pixel, and the idea behind the Windows 8 touch experience. But one does not use a vertical touch wall in real life. It is a matter of pixel density versus arm length, and while a retina-class smartphone held at waist level is too far, a 40+ inch vertical touchpanel at arms length is fatiguing and too close at it’s nominal 60dpi.
Another factor is performance anxiety – in a public space, a large interactive display effectively requires a public performance (with no privacy) and people tend to shy away from using it at all for this reason (unless they are kids!)