What do we do at that point? Reminds me of incandescent bulbs for the house.
It will be QUITE a long time before they stop making halogen bulbs for cars.
Automakers are
still making cars with halogen headlamps. There's a
HUGE installed base of cars using halogen bulbs, and unlike a table lamp or a chandelier, the lamp MUST take the right bulb to work correctly, so it's not like with household bulbs that we've seen 75W and higher incandescent types (other than specialty bulbs like 3-way or heat lamps) being removed from the market. For those wanting the light from an A21 100W filament, they can get an LED bulb in that form factor at very nearly, if not the same, output. It's not going to get anyone killed to do so. There is a wide selection of LED and CFL bulbs that work as well as, or better, than the filament bulbs they replaced (although I put a CFL in my Easy*Bake Oven to save electricity and the brownies don't seem to cook right).
However, for automotive use, there are no LED or CFL bulbs to replace the original halogen bulb-- so there is still a NEED to manufacture halogen bulbs, so that cars aren't obsolesced for want of a simple bulb to make it road legal.
Even with cars getting HIDs (a transitional technology) and more and more cars getting LED, cars are
still being made with halogen bulbs, and there's still new development in halogen bulbs, both in improving existing types and in introducing new ones-- about 3 years ago the H18, H19, and H20 were introduced (the last one being almost toylike); I'm not sure if cars are using them now or not but the bulbs were still developed.