When America and Europe have nothing to sell to the world. Actually this is already happening now. China just confidently banned all buying of American chips, not just Nvidia high end chips, but all chips, including those from AMD, Intel and Qualcomm. This means that China is now able to develop and manufacture all the chips it needs for itself and for the rest of the world. This means that the growth potential of all American chip designers and manufacturers have been capped. Without the huge Chinese markets that can buy in large volumes, the American companies cannot plan for future expansion and bigger sales. No country needs to buy big volumes of chips, expensive chips from America. No country has that kind of need and money to do so.
Chips are about the last thing that China needs to buy from America. When China does not need to buy Chips from America, there is nothing else that China needs to buy from America or even Europe. China is now self sufficient in everything it needs. This is not the only thing that would frighten the Americans and Europeans. China is going to sell to the rest of the world everything they need, cheaply and plenty, with quality as good if not better than America and Europe. This is the end of free trade for America and Europe. They cannot compete with China in quality, quantity and price. A good example is civil and military aircraft. Even if the Americans can coerce its allies to buy them, they cannot deliver them. They did not have the manufacturing capacity to build fast and in big quantities. And why would any country want to buy poorer quality, less able and more expensive aircraft from the Americans and Europe when they can get better aircraft from China?
When America and Europe cannot sell to the world, unable to compete, where are their revenues going to to come from? How are their factories going to continue to produce and to exist, to create employment, jobs, when they cannot sell anything to the world? When that happens, and is happening now, America and Europe will have no money to buy anything from the rest of the world. They can only buy and trade among themselves in their little world, by raising trade barriers. They will become an island of their own, trading and consuming expensive and lower quality goods that the world does not need.
What kind of world would it be when America and Europe have nothing to sell to the world, nothing to trade with the rest of the world? The rest of the world will be trading and enjoying the best products at the best prices they are willing and happy to pay from China. China's over capacity in all essential and useful products would only improve the quality of lives of the people of the world. The Americans and Europeans too would be buying Chinese goods and services and those made in the Global South countries. No one can refuse good value for money that does not hurt the pocket.