[bart_spoon]

It isn't rocket science. Cities in the US are pretty undesirable places to be outside a very select demographic of the population. Decent areas tend to be expensive, public transportation is generally bad, walkability is often poor, schools tend to be very poor, and they tend to have more crime. So what you get is a living situation where you either pay out the ear to live somewhere with the actual benefits of living in a city (walkability, public transportation, lots of public services/amenities), or you pay to live in an area that doesn't actually provide many of those benefits, is actively hostile to families (especially with young children), is more dangerous, all so you might have a shorter commute. So the people who end up actually making the most of the city tend to be:

- Rich, young, childless - Less affluent but still young and childless and able/willing to live with roommates

Once you fall out of those two groups, the benefits of living in an American city do a huge nosedive, and so it's no surprise that people move to the suburbs or more rural areas.

I lived in Japan for several years, and I may be overly harsh in judgements due to the fact that Japanese cities are possibly in contention for the best, most functional, livable cities in the world. But in my opinion American urban development has been an unmitigated disaster that will take decades to heal, if it ever does.