3. Many of the ghost districts never fill up before they are torn down as eye sores. Kangbashi will only fill up if coal makes a big come back, which is highly unlikely. Tianjin financial district is mostly a bust so far, but a derelict building or two for a decade is not abnormal.
The problem is really simple: China lacks a property tax, so housing is seen as a speculative investment rather than just a place to live in. And China is not wanting for speculators.