> I could imagine it might have the reverse effect. Plenty of governments would like to see their best and brightest return home
I can't speak for South Sudan specifically, but for Latin America, expatriates are a source of remittances that are very important for their birth countries' economies. $23 billion in remittances went from the US to Mexico in 2013 <http://www.pewhispanic.org/2013/11/15/remittances-to-latin-a...>. Another $10 billion to Guatemala, El Salvador, and Honduras. The US provides 78% of all remittances to Latin America, and 98% to Mexico.
I can't speak for South Sudan specifically, but for Latin America, expatriates are a source of remittances that are very important for their birth countries' economies. $23 billion in remittances went from the US to Mexico in 2013 <http://www.pewhispanic.org/2013/11/15/remittances-to-latin-a...>. Another $10 billion to Guatemala, El Salvador, and Honduras. The US provides 78% of all remittances to Latin America, and 98% to Mexico.
A full 2% of Mexico's GDP is from remittances—larger than the petroleum industry <https://www.as-coa.org/articles/weekly-chart-oil-and-remitta...>—and 10-17% (!) of the economies of the other three countries.