That’s right they are,
But all the waste heat is generated at the junction of the diode, a very tiny area. This is a problem for high power LED’s. Other light technologies do not have to deal with the waste heat in such a concentrated area. An LED is a pinpoint light source AND a pinpoint heat source. Other light technologies inherently produce their light over a MUCH larger area and it’s waste heat also. Except for focusing applications, Flashlights, spotlights or directional lighting, LED’s have another inherent disadvantage. They produce highly directional light, which produce harsh shadows. I REALLY don’t see a future for a few high power LED’s in a fixture to emulate the kind of light we want in our homes or offices. That approach creates too much light and too much heat in too small of an area to be dealt with effectively. The future I see for casual LED lighting in the future, is arrays of relatively low power LED’s spread out over a larger area. This is actually the older tech that is now available and being used by many of the in home and office lighting. Perhaps some day, LED lighting will be able to be “printed” into large sheets, so that the light is evenly spread out over the entire area. Even now it is possible to buy cheap “strips” of led lights from FastTech for a very reasonable price. Here is the Link
About 1200 lumens for $10. Notice that the strip does not need ANY heat sinking. That’s because the light and heat is spread out over the 16 feet length of the strip, 300 led’s. Our own texaspyro used this type of light to great effect here: Replacing Lumiline light bulbs with LEDs
to simplify: for Flashlights, spotlights or directional lighting, high power led’s with massive heat sinking or active cooling. For in home or office, or anywhere where directional lighting is undesirable, large arrays or strips of many low power led’s. I really don’t see anyway around it, the physics will not allow it.
BTW, even older lighting technologies, Incandescent, florescent, etc. that already produce their light over a larger area, still rely on diffusers to try and emulate an even larger source of light. Look around your home or office, Incandescent bulbs are frosted (soft white), ceiling fixtures have frosted or white globes, even 4 foot florescent light fixtures will have diffusers or a reflector to spread the light out even further.
Go outside at noon on a clear sky, sunny day and you will see a sharp shadow of yourself and other objects. On a clear day, the sun is a point source of light in the sky and is focused (because its great distance) and casts sharp shadows. Then go out on an overcast day and you will not see any shadow. The entire hemisphere overhead is the diffused light from the sun, and appears to us as an “infinite plane” light source. An infinite place light source casts NO shadows, and it’s brightness does not vary with distance. THAT is the best source of light for every day living.