Because they are the ruler of the world. They have 60% of global GDP, they have the dollar and the entire world finance runs because of them, they have the entire world tech stack under their control.
Compared to that, what does China have? Just some production of goods? Just production alone will not give China superpower and the ability to do what it wants. They need to create brands, standards and systems.
They need to export not just their goods but their software tech stack, hardware standards, their currency. Essentially become an alternative of the west. Otherwize, when the war starts and China gets cut off by the west, not many countries will fall into the China camp.
If the choice is between trading with China and trading with the west, pretty much every country will choose the west, even if China is their biggest trading partner. Because access to western market, finance and tech is more important than trade with China. This is the biggest Chinese weakness and it must be overcome before China starts the Taiwan war. Cause the west will impose heavy sanctions on China and force every country to enforce it.