Many of those governments ardently desire their intelligent, rational people leaving, and will even facilitate that movement. They get in the way of a stable tyranny.

More importantly, the more they appropriate a foreign culture, the more the locals will see them as "foreign". A "Return of the Elites" might not be welcome: see Iran after the Shah was deposed,

Capitalism as the source of a nation's prosperity might also be a red herring: notice how America and Africa are full of perfectly capitalist, utterly miserable nations.