Communism has always failed. The reason is simple: It destroys wealth and thus becomes corrupt. Individuals create wealth. Governments always consume wealth and become corrupt whenever the wealth of their nation declines. Their wealth declines because their system of governance destroys individual incentive to create wealth. Corrupt governments are always incompetent because they jail, or even kill competent competitors.
Xi by his own words is abandoning communism and transitioning to a new and undefined governance he calls China Socialism. The new mega cities are not suited for communism but rather for socialist governance of a different nature
You note individuals and the creation of wealth. The wealth of China was created by a host of individuals with unprecedented freedom of action. Xi is now in the process of ceasing thet limited freedom and using government owned corporations, taking control of corporations and family businesses. The outcome is not defined but seems to be some hybrid arrangement with government control of some form of corporations that have stockholders.
Jack Ma is gone as principal stockholder but Alibaba lives with government majority ownership.
My observations result in this finding
Government is organized crime, and because we need the organization, we tolerate the crime (until it becomes intolerable).
Many government jobs are part of an entitlement class. They do not see themselves as useless parasites damaging their own society.