They can. They just won’t.

Here are the tracks left by one of the sidewalk snow plows by a park in my neighbourhood.

You know, the plows that “won’t fit” on the sidewalks in front of people’s houses, but somehow manage to fit on the bits of identical sidewalks adjacent to city property — parks, schools, bus stops….

Evidence that sidewalk plows CAN fit on my neighbourhood's sidewalks

As Spacing says:

The real reason is that the old pre-amalgamation City of Toronto didn’t plough sidewalks, and the city can’t afford the extra equipment or manpower it would take to extend the ploughing throughout the central area. Which is fair enough, but don’t pretend it can’t be done — admit it just won’t be done.