Is $1800 really "cheap"? That might be cheap to people who are making close to 6-figures, but that isn't remotely affordable for a large percentage of the population.
Life-long Brooklyn resident here. Not it isnt cheap...i dont think anyone claimed it was cheap -- they just claimed that high-density housing (like Manhattan and northern Brooklyn) is more effective on a relative scale as compared to the Bay Area.
I've tried to make the math work every which way - the Bay Are is just out of control, even compared to NYC prices. NYC compensates quite well by building upwards rather than outwards, this has a second benefit of reducing commutes (again, on a relative scale compared to the Bay Area.)