The ghost cities have attracted residents over time, but they're still mostly empty. Constructing buildings that sit vacant for a decade or more is not very efficient - and the buildings depreciate with age whether they are occupied or not.

Gluts and shortages are endemic to centralized economic planning.

You’ve moved the goal post/claims from “completely vacant” to being vacant for a long while and depreciating.

Yes, they were completely vacant for many years.

There's nothing efficient about that.