>Tell that to all the people who could easily live on the vast swaths of property suburbanites have set aside for doing absolutely nothing with (lawns).

People could not "easily live on the vast swaths of property suburbanites have set aside for doing absolutely nothing with (lawns)." For one, lawns serve a useful purpose (groundwater / aquifer recharge, flood control, etc). For two, https://www.google.com/search?q=kowloon+walled+city