Save perhaps rarely if ever used seating positions (middle rear of the super stripped down V6 Mustang they make like 10 of so they can advertise a starting MSRP or some other comparable niche) I don't think seatbelts are going away anywhere they matter.
Ditto with headlights and tail lights, drivers find them useful. Perhaps we'd see a delete option used by fleet buyers who intend to equip the vehicles with alternative lighting.
Oh, wait. That’s what regulators are for :-)
Do you blindly assume that regulators are right 100% of the time? If they aren't , then by virtue of regulation being never removed in the long run, you will end up with inflated regulation for which some of it is done for no good reason.
Is there a particular regulation you would prefer to remove? If you list something specific, let's talk about other alternatives to removing the regulation that could cause better outcomes without reducing supply in that market.