More or less. A few years ago all we had were 5mm LEDs; back then the output wasn't much, but it was an exciting new development. Never before had there been such a thing as efficiency in portable lighting.
Then we got Luxeons, and the trend of lights with just one bright LED instead of arrays of small dim ones started. But they still had trouble beating incandescents, and they were much more expensive than the latter, so most people preferred the old technology.
Then Cree came with the P4, which definitely could beat incandescents, and revolutionized the world of flashlights. That's when LED lights became a feasible idea for everyone.
Since then the improvement have been evolutionary, not revolutionary. That's not to say there hasn't been anything significant - quite the contrary, in fact - but it's unlikely (not to mention possibly physically impossible) that a new LED will hit the market with twice the efficiency of today's Crees and revolutionize everything again.
Relatively new, yes. The earliest 5mm LED flashlights that made any sense date back to year 2000 or so, I think.
There's a
lot of interesting data about LEDs and early LED flashlight designs in Daniel Rutter's reviews. The whole category is
here;
this is, I think, his earliest flashlight review, but the product isn't exactly sensible.
This should be the first review of actual generic flashlights. You can go on reading the various comparisons in order of time, then look at the other reviews. He's stopped reviewing flashlights after one with a Cree P4 in it, so you'll find nothing about anything that came out in the last few years, but the rest is good-quality reading.
I know I'm in the minority here, but I disagree. I spent some time gathering various lights, but it was in the search for the perfect EDC. When I found it I stuck with it for years, with no real need to buy more stuff. Technology has marched on, so I recently replaced it with a SC600. I foresee this one will last even longer, and I don't really plan on buying anything else in the meantime.
