Most of those "ghost cities" got populated in "just a few years", so much so that wiki had to change Chinese Ghost City entry into "Underoccupied Developements". And what is the scale of PRC "malinvestment", quantify or approximate it. Here's a hint, PRC RE+construction as % of GDP = ~15%, about OECD average. PRC just very good at building and gets much more from it, even if some sits idle first or ultimately gets wasted. AKA PRC barely throws more money that OECD in RE sector, they certainly have the option of throwing less money, but that only makes them more efficient relative to rest.

Entire construction + downstream industries is 30%, most of 15% redirected to renewable row out where solar already has better ROI than importing oil, aka, until PRC displaces another 10m barrels per day via renewables, or hits US per capita energy use (double current), any domestic power investment is positive. Throwing money at increasing cheaper power that makes manipulating atoms in every down stream sector is directly what market forces is ALWAYS driving towards. Increasing energy per capita is the only proven winning civilzational development strategy.

Don't confuse some malinvestments for retarded existential PRC collapse narrative. For reference US spending 18% GDP on health care, i.e. 2x OECD average of 9% is single handly more inefficient than likely ALL Chinese policies can misallocate, i.e. that 9% of excess US health spending that gets wasted by scribes can build entire PRC HSR network in like 5 months.