My suspicion is that WUSB died because it used UWB which was/is very difficult to hack. The signal looks like random noise distributed across a wide spectrum a

My suspicion is that WUSB died because it used UWB which was/is very difficult to hack. The signal looks like random noise distributed across a wide spectrum and if you don't know the secret key it's hard to tell if there is even a signal there. If WUSB had made UWB widely available and cheap it seems likely it could have been hacked to create cheap very secure point-to-point wireless links for anyone and everyone. UWB has been around for a decade or so, but there are still few commercial products and the ones that do appear tend to later disappear into the military world (e.g., Aetherwire). The one exception is UWB tracking tags, which Samsung just introduced and Apple is about to introduce (and there are several other companies making them like Nanotron). Precision location has some great applications but also some scary ones. Non-interceptable secure short-range data links may soon follow if the tags/phones turn out to be hackable. It will be interesting to see how this current foray into UWB goes.