They have drowned their municipalities in debt cumulatively equivalent to the US federal and state debt as a percentage of GDP. Localities aren’t allowed to tax but are responsible for local services and industry. Local governments borrowed heavily to hit GDP growth targets and compete with each other for investment and talent.
There is now a backwards migration of the working class back to rural towns from the cities because the incentives China gives is towards technologies that only benefit their already upper-middle class workers. About 500 million Chinese live in rural areas and over 20% of their workforce toils in the fields. That’s not changing anytime soon. Youth unemployment has been 15-20+ percent for some time.