This is a super simplified and somewhat wrong interpretation of trade dynamics. Surpluses are important because 1) sustained surpluses imply structural reasons, and in this case, China's consistent upgrade in industrial production chains as it uses the funds it has acquired to invest in improving technology and human resources. 2) sustained deficits are often correlated with domestic employment moving away from manufacturing and into services, as well as a bigger share of income by corporations who are able to offshore their production, leading to greater inequality. 3) The dollar will not maintain its purchasing power forever, if its manufacturing, R&D and military dominance are perceived to be eroded. Many countries are moving away from sole reliance on dollars as the only reserve as we speak, including China. The amount of US dollar assets China has divested over the years is staggering.