The Myth (?) That City Growth Causes Suburban Poverty

One common "story" about the evolution of American cities is that suburban poverty is growing because people are being driven out of high-priced cities into suburbs.  One possible implication of this argument is that cities need to be kept poor and stagnant so that poor people can afford them.

But there are a variety of other possible reasons why poverty might be growing in the suburbs. First, the stagnant economy has caused poverty to grow almost everywhere; thus, people who already lived in suburbia have slipped into poverty.  Second, city-to-suburb migration might just be a continuation of the sprawl pattern common in the late 20th century.  City residents have been leaving low-income neighborhoods near the city core for further-out neighborhoods for decades; the only change in recent decades is that their new destination is outside city limits.  Such migration might increase suburban poverty rates if the city residents are more likely to be poor than their new suburban neighbors. 

Having said that, I'm not sure we have data to prove this point: how do we know who is leaving cities for suburbs?  Having said that, we do know that cities generally still have higher poverty rates than suburbs, which suggests that cities are not running out of poor people.  Even hyper-expensive Manhattan has a 18.3% poverty rate- lower than some other boroughs, but higher than that of New York's suburbs (most of which have poverty rates in  the 5-10% rate).