The problem is cities are full of poor people, for various lamentable and not so lamentable reasons. That fact drives all the other things that drive people out of cities: crime, bad schools, etc.

The sorry state of American cities is due in huge part to state distortion. The social services for the poor are heavily concentrated in the cities, so that's where they go (has the irony ever occurred to anyone that people complain about not being able to afford SF, NYC, etc, but at the same time those places are filled with poor people living in project housing?). Social services for middle class people (roads, good schools, etc) are concentrated in the suburbs, so that's where they go. Then the municipalities prevent all development, causing skyrocketing rents for people who want to try and live in the city anyway. City and state governments try as hard as they can to get people to leave their cities.