In NYC, it depends heavily on the bus line. Some stop nearly every block (which can be as little as every 100m) whereas some have more widely-spaced stops. The buses here are notorious for running very slowly (and thus behind schedule), and one of the proposals to speed some some slow buses is to eliminate stops on lines where they are densely clustered. It's become a subject of considerable debate, as residents and…
The "local" stops on a lot of Subway lines really shouldn't be there. I'm looking at you 18th Street, 28th Street, 50th Street and so on. 18th Street in particular is 4 blocks away (where 1 block = In the other direction 23rd Street is 5 blocks away.
The Subway spends billions of dollars a year on power. Most of that power (for trains) is spent accelerating so every stop counts.
I expect the same people who are against consolidation of bus stops are against consolidation of Subway stops.
Honestly I personally have never taken a bus in NYC despite living here for nearly a decade. Distances in Manhattan are just so relatively short.