Quality of life is very subjective though. Americans by and large are anti-social, so these sparse layouts/nimbyism are a result of that. This in turn reinforces living patterns which may or may not be optimal for any given person. Again, they may be social enough on their own terms, but insufficient to want to live closer to others for a variety of factors, manifesting in very real differences in civic planning. I would look to this behavior need to change before any substantive zoning/transportation changes are really adopted.