A big +1 to this as I thought this was the best post in the thread so far. (bold emphasis mine)
Even given the unlikely example in OF's post, LED has a better chance of successfully matching the efficiency and output in the future than it ever has of matching the throw performance of HID. While throw performance is related directly to surface brightness, the topic of this thread is "output" which I generically take to mean overall lumens produced. If they can overcome the heat issue, overall lumen output will eventually become possible. On the surface, this obstacle may sound like a simple matter of time and development but it's actually a fairly large gap to overcome. The materials for example aren't going to change than much in the next decade. LED light makers are still stuck with the typical aluminum, copper, brass, ti, SS, ect. The LED dies themselves are also somewhat fixed with the patterns and materials we currently have, so unless new materials are developed that can handle twice the heat in half the space it will remain a barrier. Active or some other means of hyper cooling seems to be the only hope for the near future.
To match the throw of a current 14W HID it would roughly take a die size one half the surface area of the XP-E while producing more than twice the output, resulting in much higher surface brightness. To use OF's phrase, "it's just not happening" now or anytime soon, especially considering the rate of LED advancement we've seen over the last 2 years. They've made advancements but nothing close to what would be required to close the gap. I'm speculating that at some point LED's will undergo some revolution or a completely new technology will emerge.
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