SF made an exclusive deal with Ford GoBike, the expensive docked bikes that are never nearby when you need them. That pre-emptively barred these companies from launching their dockless bikes in SF, and so the scooters are the workaround. And as someone else points out, scooters are scary on the street, so now we have a sidewalk problem. This is 100% the city’s fault for saddling us with old bikeshare technology.