San Francisco's zoning makes it illegal to build apartments in 73.5% of the city 8 years ago
That assumes that building more creates more diversity among the services or that the people living there are the McDonald's kind of non-picky persons that accepts whatever is being served.
People move to dense areas in belief that a dense city has more to offer in terms of jobs, but end up moving to country-side in their mid 40s despite commuting due to realizing what truly is quality in life.