International shipping from China to the US is subsidized by USPS under the Universal Postal Union rules since China is classified as a developing country. Terminal dues to the US have been increasing over the last 5 years to compensate for this.
https://www.ecomcrew.com/why-china-post-and-usps-are-killing...
It's still crazy to me that we classify the second largest economy as a developing country. Especially when said "developing" country is trying to flex it's muscles over the world stage and attack its neighbors.
China can either remain a developing country subject to rules imposed by developed countries. Or it can join the developed countries and shape those rules. It can't do both.