Sometimes scooters are parked on the side of the road. Sometimes scooters are parked in a ditch beside the road. Bikes rarely are.
Speaking from my experience in Shanghai, where bicycles are common, there's no such thing as a bike rack. (Well, I have seen racks for rental bikes. But none for individually-owned bicycles.)
Rather, supermarkets, university buildings, apartment complexes, and other places which are likely to receive a lot of incoming traffic have bicycle parking lots, and if you're somewhere else, you park on the sidewalk.
Scooters can be parked at bike racks. Are there enough bike racks to park the scooters at the bike racks? would the situation be similar if all of those scooters were bicycles or if bicycles were as cheap as scooters?