NYC fully meets the definition of walkable.
(BTW, I am lumping in biking with "walkable". A better term is "active travel")
Slef driving would probably make the car problem worse.
But it’s hard for me to think of a city I’d rather walk between to random points in.
In the US? Sure. Now imagine a place where there are hundreds, thousands of cities that walkable or better, and you don't have to be a gazillionaire to live in one.
Based on my recent visit to New York, the main traffic issue I saw was really bad light timing. This trains both pedestrians and drivers to ignore the traffic signals.