Text and database entries are, indeed, Vastly lighter on resources (compute and bandwidth). Bandwidth cost for text is practically free. Managing voting is surely not easy though; every single vote is an additional database entry which means that they cost money to store. Then the vote sorting algorithm has to run pretty frequently. Comments themselves are probably nothing compared to the votes.

But managing voting and sorting is a one-time-cost. Reddit doesn't let you vote on old things which means that they can completely discard the votes and keep the totals and never resort ever again. They have no real ongoing costs there.

It hasn't been productized yet to my knowledge; the technology needs to be licensed from the MIT Technology Licensing Office.

https://tlo.mit.edu/technologies/high-efficiency-incandescent-lighting

I would bet that nothing will happen until the patent expires in 2033 and only then will products magically appear, just like what happened with 3D printers. Laws will have to be updated to specify efficiency requirements rather than underlying technology which was obviously a mistake.

I personally think that LEDs have their place but other types of lights are still useful and sometimes better, like directional incandescent MR16 bulbs and arc lamps like I mentioned above. LEDs will get there soon but aren't there yet. And by that time maybe they'll be obsoleted by newer technology!

There is also the fact that electricity is about to get vastly cheaper due to vastly cheaper batteries and solar panels, to the point where LEDs may be bad for the environment compared to much simpler and much cheaper-to-manufacture traditional incandescent lights. The world of lighting is changing fast!