These American immigrants have strange manners, as the Chinese see it. They never share food, and they finish everything on their plates. They always ask locals they meet, “How many children do you have?” — even though the answer is always “one.” They are always inquiring about politics.

But they thrive. They put their energy, skills and family networks to work; they reap great success. They run burgers-and-fries joints, English-language academies, fitness centers and even an intercity transport service known as the Americatown bus.

In “The Warmth of Other Suns,” the author Isabel Wilkerson has written feelingly of “what humans have done for centuries when life became untenable — what the pilgrims did under the tyranny of British rule, what the Scotch-Irish did in Oklahoma when the land turned to dust, what the Irish did when there was nothing to eat, what the European Jews did during the spread of Nazism, what the landless in Russia, Italy, China and elsewhere did when something better across the ocean called to them.”

Yes, she says, “They left.”

A considerable number of Americans already live and work around the world. But to meet them in Bangkok or Bogotá or Sydney is to encounter, for the most part, an educated elite that has emigrated out of choice — or members of the diaspora who straddle two lands. They usually had good options in America, but still chose to leave for the thrill, or a higher paycheck, or the chops of investing in a hot new market or renewal after divorce or other failure.

What has not happened is a pattern of working-class emigration out of America, as one sees out of Mexico or Ghana or Cambodia.