Source? Maybe legal emigration increases, but I doubt that illegal or asylum-seeking emigration would increase. People are fleeing from the terrible conditions in their home countries.

This premise was discussed a few times prominently on HN, and it appears to be accurate. There is an initial surge in people leaving as a country climbs economically; then it tapers off and reverses after you get rich enough to support what I would guess is a broad middle class quality of life.

"New Research Confirms that Migration Rises as the Poorest Countries Get Richer"

"As GDP per capita rises, so do emigration rates. This relationship slows after roughly US$5,000, and reverses after roughly $10,000"

https://www.cgdev.org/article/new-research-confirms-migratio...