They may think that way because of many things: Nationalism, the dollar standard, Best in basket ball(well now thats my opinion), they started the U.N. and is a permanent member(theres only 5), and because many nations sorta depend on them(supplies to help countries). They are a trading partner as well.
As for China being around for thousands of years, the PRC was established in 1949. Before that things were way different. Even before that, we still weren't unified. warning kingdoms fought many wars + more