Seatbelt issue is probably going away.

My car will nag the hell out of me if anyone isn't wearing a seatbelt at speeds over 20 km/h. I assume this is true for most modern cars.

Part of the population who didn't grow up with seatbelts is aging. I remember my late grandmother hated the seatbelts, they didn't exist when she grew up. Often she would pretend to use the belt, holding it in place by hand so that it looked like she was wearing it. Stupid, and illogical, but that's how it is..

That only leaves the "cool" youths. Once "modern" naggy cars become old and cheap enough for them, they'll probably start too (or go out of their way to disable the sensor, or uncomfortably wear a seatbelt behind their back - turning a passive action into an active one.).