You probably can't imagine the kind of initiative it takes to leave where you are to start fresh somewhere else. THAT's the self-selection I am talking about.
My parents’ and their siblings and all of their extended family left their country to go to US and UK. But they all had homes and networks and a place to go back home if things went sideways. The collective wealth of their network is sufficient to provide its own safety net.
Contrast that to someone in the home country who might not have that network, and who landed a decent government job that affords enough to feed and shelter and educate family.
This person will not have the “initiative” to throw away a relatively sure future because they do not have the ability to count on friends/family to support them in case they fail.
