Foreign cities that are clean and nice tend to be both very homogenous and high median intelligence. In the absence of homogeneity there will always be defector

Foreign cities that are clean and nice tend to be both very homogenous and high median intelligence. In the absence of homogeneity there will always be defectors who are willing to externalize costs like litter disposal. In an excessively downshifted intelligence distribution there will be insufficient productivity and developmental capacity for a high standard of living. There are few/no large cities in the US which meet these criteria.