Depends on what media you're reading I suppose. Quite a lot of it paints SF is a city of haves and have-nots which fits nicely into the above poster's experience.
I've lived in a lot of places with, in many states, in many countries, all with different population densities and economic diversity... and that statement holds true for all of them.
One of these days the sheer weight and remaining shelter of class consciousness will break through the cognitive dissonance. One of these days.