As a rule, any society that is single-mindedly interested in its own promotion and thus in the survival and preservation of its culture would have to have a huge population and send its people out, not letting too many others in.
The European nation states send a lot of people out, but do not have huge populations, and let everyone in. The USA has a huge population, but sends not enough people out, and lets everyone in. Japan has a big population (twice the size of Great Britain or France), lets no one in, and sends few out. China, India, and the Islamic world come very close to the ideal of a society that has the means to let its culture survive for a very long time.
Pattberg, Thorsten (2013), The East-West Dichotomy, Foreign Language Press, Beijing