Counterpoint: if ̶b̶i̶c̶y̶c̶l̶e̶s̶ cars were a new invention that came out this year, would they be allowed on the road? I'd say almost certainly not

absolutely they would - not just on the road, but also on the pedestrian pavement, everywhere. Case in point - electric scooters.

Why not? We allow haven't even banned those electric one-wheel balancing things that if they lose power will face plant the person riding it.