I believe, after research, that people cannot make a community of a habitation exceeding certain numbers, that small is beautiful, that failure to make real communities produces most of the discomforts and brutalities associated with big Cities. That 20,000 is about the ideal maximum population; that thereafter expansion causes an exponential rise in social problems: for which provision for extra social services, however great, can never catch up.

Conclusion: Mill Valley is quite big enough as it is. More people or more jobs will be less happiness, less comfort, less relationship between people.
Keith Wedmore: Author of Chapter Social Pathology and Urban Overgrowth at p 293 of "Mental Health and the Environment", Churchill Livingstone, New York, 1984. Chapter described in the Lancet review as "incontrovertible"