Comment by IAmBroom

Another optical engineer here.

I used to wonder WTF was so hard about LED lighting. One R, one G, one B, a shunting resistor and... and then I took a glance under the hood. Oh. Yeah, much dicier than heating up some tungsten and frosting the inside of the bulb.

(Yeah, inventing cheap blue LEDs was some serious heavy-lifting in itself, but that hurdle has been jumped.)