NYC is also the most densely packed city in the US. There are places in the city where the sidewalks get so dense during commute/tourist hours that people cannot fit, pushing pedestrians out into the streets and bike lanes. 8th Ave north of Penn Station at 5:30pm is a prime example of this.

There's simply no room to have lots of discarded dockless bikes/scooters in such an environment where there isn't even enough room to walk, and they would be treated poorly. Docks/exclusion zones for the most congested foot traffic areas are necessary.