It appears Valve intends to launch Vive with a tether. It may be that they launch the tech platform as an open standard and they simply didn’t care to solve the tether problem? I don’t think having people clear out a room for VR is a show stopper, but I do think a tether, even if it turns out to be practical is a conceptual show stopper for most people.
Could LiFi with enough pickups do it? Or is it the idea of having to modify the room too much? Valve has a system that gets its positional info from leds so LiFi has to have occurred to them? Maye its a power issue?