Are you saying that if San Francisco has more people, it will become more sustainable and affordable and people will be happier? Of course that's a broken caus

Are you saying that if San Francisco has more people, it will become more sustainable and affordable and people will be happier? Of course that's a broken causal chain and obvious straw man. You have to start out with more and cheaper housing. Economic analyses indicate we could build a huge amount more housing, and people would snap it up. Build enough to actually bring the housing prices down, and yes, there would be a much more vibrant and diverse city life. (But the market has to follow this naturally. Legislating prices lower will have the opposite effect.) As far as cities being "sustainable" -- cities draw resources to themselves. That's simply how it works. Sustainability is something that only matters in the economy as a whole. Cities need not be locally sustainable to generate wealth and to be a positive benefit to society. Paint that picture for me, please. New York City in the past. Houston in its run up to becoming the 4th largest metropolitan area in the US. Chicago in the past as well. San Francisco is artificially held back from the density the market in other cities have achieved.