In China’s Inner Mongolia province, in the middle of the Gobi desert, row upon row of largely vacant apartment towers line the streets of Kangbashi, a new district of the city of Ordos. Earlier this month, Xu Yongfen and his family moved into one 28-story building. In the hallways there are a few signs of life—tricycles, slippers and pink children’s shoes in front of some doors. But most apartments remain unoccupied, their doors still covered in plastic wrap, and at street level, barren storefronts are visible in all directions. “This area is nearly totally empty,” Mr. Xu says, tapping a cigarette into a bowl of ashes...