You left out an important though short-lived development: About 1905 or so, the Prest-O-Lite company began making refillable acetylene cylinders which could be mounted to the automobile’s running boards. These tanks provided a large refillable reservoir of acetylene for the headlights, eliminating the caustic sludge problem and the need for frequent refilling of the carbide and water. These systems quickly replaced the carbide lamps and remained the standard for ten to fifteen years until electric lamps became reliable enough to replace them in the late ‘teens.

LED’s last tens, if not hundreds of times longer than standard bulbs. That is why you will have congress critters dragging their feet or blustering about the “shortcomings” of LED bulbs as they pocket GE’s, Sylvania’s, Philips, and others money.

Contrary to your statement, the majority of drivers are in fact what you call “old farts”. to get a clue, do the math on populations and aging. They will always be the majority.

Also, contrary to your statement, old eyes are not more sensitive to certain spectrums of light. Old eyes typically become less sensitive to any particular spectrum.

How old is “old fart” in your book? 30? The HIDs do a great job of illuminating the road for the driver — but if that driver doesn’t keep the headlights clean, the glare blinds other drivers.

I’m about thisfar from installing a bank of KC lights on the top of my car so I can return the blindness factor at every HID user who doesn’t properly maintain clean, glarefree headlights.