You said LEDs have the potiential to be really cheap, is it because they require less energy to manufacture than HID lamps? I read that if intergrated driver circuits are developed for use in A-line retrofit lamps they may almost be as cheap as incandescent bulbs!
It is not, because the LED process would be simple and cheap, but because with one object going through the manufacturing process you make tens of 1000's final LED dies at once, while with HID you have made only one burner. When you divide the wafer price tag by the high number of product made of it (by rather low tech processes), you end up on cost really hard to beat by other manufacturing methods...
The same apply for the driver chips.
So the saving is in the manufacturing method, but that can not be used for the "classic" light sources, as it is limited to flat things made of layers and operating on way easier conditions (loweer temperatures,...) the materials alone could handle. All the classical light sources push the materials to their limit - tungsten nearing it's melting point in incandescents, arctube material it's softening temperature in HID's, while semiconductors are operating up to 150degC (with 200degC peak), while the weakest functional material there, the aluminum for interconnections on the die, melts at 500degC - so about factor of 5 margin for the temperature rise...
