You can add Costa Rica and Argentina to that list.

Back in 1900, Argentina literally had the world's highest GDP per capita.

Nowadays no one would ever think that Argentina was ever much of anything, let alone once being the home of the world's averagely wealthiest people. What happened? Well, at least one cause is demographic change. That is, that large numbers of people left those more dysfunctional countries to Argentina's north (particularly Paraguay and Bolivia) and migrated southwards. And by the 1990s, no longer was it merely Hispanics, but large numbers of people foreign to the continent (e.g. African blacks) who were arriving en masse. Unsurprisingly Argentina—particularly population centres like Buenos Aires—now resembles those same countries that many 'new Argentinians' fled.

It seems that migration will eventually create a sort of global domino effect. That is, that if many immigrants come to Argentina, perhaps more established Argentinians will go to, say, America, to avoid the nonsense they bring. And when many immigrants come to America, perhaps more established Americans will go to, say, the UK, for the same reasons. And when many immigrants come to the UK... you get the drift. What happens when no place is appealing to migrate to? Everyone is stuck with nowhere to go. First-world peoples have to put their foot down somewhere and assert: 'This is our land, we don't want to live like the South Africans, Argentinians, and, look at this long list of people we don't want to be like, so get lost, we're full'.