"Skilled migrants who leave for a rich country never come back."
False. A striking example comes from recent research in the Pacific, which has amongst the highest rates of skilled emigration globally. Consider Tonga, a small island nation with a population of only 100,000, where skilled workers might stereotypically be thought to have little incentive to go back. Even in this case, by age 35, just over a third of the nation's academic brightest who had migrated after high school were already back working in Tonga. And in Papua New Guinea, half of the most academically skilled migrants had returned home by their early 30s.
In the United States, more than 20 percent of foreign students receiving Ph.D.s already have firm commitments to return to their home countries at the time of graduation, and many more will likely return in subsequent years. Of course there is large variation across countries: Migrants are much more likely to return to booming economies with good job prospects, as is seen by the flows of Indian tech workers back to India in the last decade. But even in cases where few migrants return, those that do may be particularly motivated by a desire to help their home country and may return to key leadership positions. One recent calculation finds that since 1950, 46 current and 165 former heads of government received their higher education in the United States.