As I understood it city streets are harder to clean because you can’t just drive a truck with a blade and push snow to the side.
It is a time consuming task of having to load snow on dump trucks and then driving those trucks somewhere to dump the snow. All of that is much more time consuming than driving a truck with a blade on the front and pushing snow out of the way.
In the suburbs, you generally can’t park on the streets during winter (at night anyway). And the front lawns are deeper. In the city, the cars are more likely parked on the street, and the houses practically come u to the sidewalk. One or two stalled cars in a side street requires a tow truck, a high lift and dump trucks. It just takes longer.