You are correct, the “ghost city” claim is about a decade old and in the time since then good functioning cities developed incorporating those infrastructure and urban resources built previously.
Zhujiang New Town for example can house up to two million people (often moving out from the 7-10 million living in the old areas) and while I dislike the urban planing of it, it was once among the foremost called “ghost city” in propaganda, yet it is larger than most cities in most states of the US as example.
I also agree that having too many flats seems to not be that bad a problem to have. Especially when 2‰ of the US are unhoused - even though there are millions of empty flats.