Heat generated by incandescent bulbs may not always have been totally wasted, but it was almost always wasted. It is resistive heat, first of all, which is quite inefficient. In homes, better to save on that kind of heat, and use heat pumps or other methods, for heat. And in traffic signals, if you want to argue that heat from incandescent bulbs helped melt snow, true as that might be, it only applies for the relatively small amount of time, per year, when it's actualy snowing. Other times, it's just waste. Better use a separate system to melt snow, only when needed.
Plus, incandescents get really really hot, which always best to avoid.
The other aspect of this is that LEDs last a very long time, and as far as I can determine so far, also much longer than CFLs. I've had only one LED quit on me, no doubt the power supply. I've also dropped an LED flashlight once, but it kept working fine. Incandescent filaments tend to break, in similar circumstances.
And you can buy LEDs of different color, to meet your needs. The 2700K ones seem virtually identical to incandescent lights.
Of course, some people might be tempted to add brightness instead of purely saving energy. Overall, though, that's not an indictment of LED bulbs. More one of wasteful people. LEDs now sell for prices that have become thoroughly competitive with incandescent bulbs, especially when you figure in the much longer life, so hey, it's all good!
The key is not reducing, but REVERSING. Reducing is a surely a positive step. Our lungs and air does not need lesser CO2, but a purification (reversing). Do doctors, who see a patient who lack oxygen, give them lesser polluted air ? Nature's renewal, as is, will take a very long time to reverse anything to suitable levels.
"One might think that the big reduction in consumption by lighting and electronics would've led to a stark reduction in per-capita electricity consumption" :
Light has never been one of the big items. Looking at the entire energy usage, it is less than 2%. Shaving 50% of 2% does not do much.
One might think that the big reduction in consumption by lighting and electronics would've led to a stark reduction in per-capita electricity consumption, but the reduction is minimal. The worst offender is the air conditioner, which has only gotten worse as houses have increased in size and more people have moved to locations where they never would have lived without AC. Houses are getting less efficient, if anything. The incentive structure is poor and there is little desire to invest money up front into efficiency.
I see that where I live. On the days when the conditions are worst, some of the stoplights are completely obscured. It seems like outright negligence not to have put a simple resistive element and temperature sensor on the face of the lamp.
Figures 1-2. and 2-1. on PDF-Pages 11 and 16Are even more clear.Only the newest LEDs are good enough to be more efficient than CFL.
I always favored CFLs and there the ballast makes the difference. Just the big old heavy inductor is inefficient compared to a current limiting SMPS.
"I've read that the reduction in cost of light has resulted in more light being used, making the world even brighter. In that respect LEDs are backfiring somewhat."
That is what I immediately thought. I see it used as decoration and burning all night.
Also the color tone is different to the Sodium lights that are being replaced with LEDs.
Blue LEDs are used by some as decoration, I do not like it.