Home Economics: “As Gyourko points out, in the year 2000 the median house price in Philadelphia was $59,700; in Detroit, it was $63,600. Those prices are well below the actual construction costs of the homes. ‘To build them new, it would cost at least $80,000,’ Gyourko says, ‘so there’s no builder who would build those today. And as long as those houses remain, the people remain.’”