I have no single theory or special insight; such punditry is cheap and easy and meaningless. But I suspect it was a combination, in hard-to-figure proportions, of several factors:
It's not clear what actual market need UWB served
A lot of the UWB enthusiasts were in it for their own self-interest (selling ICs, and related software), rather than to meet genuine end-user needs.
Sometimes, the market simply can't handle another specification or proposal, even if well-intentioned; there's "new-initiative" overload and active resistance or, at the least, passive indifference.
As with so many developments, UWB was overhyped by its proponents, and yet under-delivered. The message seemed to be "whatever your high-speed wireless connectivity problem, UWB is the answer." But, you have to read the "is" in that phrase as really being "may be", since there are a lot of unknowns here.
Anytime you are dealing with wideband signals, and short pulses, you have regulatory issues on top of EMI/RFI and co-interference concerns that can't be ignored or waved away easily.
There were (and still are) genuine technical, component, and operational issues related to a solid, reliable UWB design and protocol that can't be ignored or dismissed simply by wishful thinking.
And we can't ignore that the costs of UWB were likely to be higher than the market could accept.
So, what do you think? Was UWB just ahead of its time, as is sometimes the case? Was it ill-conceived from the start? What has apparently killed it? And can it come back?♦
Sorry, to me, it has failed in the reality of the market, there are no products to buy on the shelf at Staples, Best Buy, etc, no industry momentum, and so on. And while it may rise again, that's very unusual (though not unheard of) in this fast-moving world, espcially if the reason was that it solved a problem lots of people didn't have, or think they had. --BillS
As the founder and CTO of Pulse-LINK the oldest UWB company in the CE space I could write a book on UWB. Why did UWB fail? The fact is UWB didn't fail. What failed was a specific implementation of UWB known as WiMedia. When people think of UWB they think of UWB from Intel known as WiMedia. The term UWB has more to do with a unique spectrum allocation than a specific implementation. Saying UWB failed would be like saying 2.4 GHz failed because "Home RF" failed (Another discredited wireless standard pushed by Intel). So while there have been some notable failures in the 2.4GHz space, There are also many examples of 2.4GHz products that have succeeded such as WiFi and Bluetooth. Just because WiMedia failed does not mean UWB failed, WiMedia failed.
One last comment. Bob Groh's comment above about UWB being "over hyped". There is some truth to that, but UWB does have some truly unique abilities that to date have not been fully exploited. Abilities that bring real and significant value that can not be done with any other solution. While it is true that WiMedia failed, UWB has not. UWB is not done or over. It's just getting started
I think you hit all the points in your writeup - to me, it was always super-hyped. I remember when it first hit the news - UWB was going to revolutionize the world! As I remember it, they were touting short range radar that would easily penetrate walls, etc, etc. Wow!!!! Well, I always thought 'yeah, sure (add hint of sarcasm here)'. No, I think UWB is nothing more than an extension of regular technology. And regular technology with frequency hopping came along and achieved the same ends (mostly) as UWB in a more acceptable and readily achievable manner.