But what if people could migrate from the developed world to resource rich regions (like Africa and South America) and have the chance to unlock the potential of those regions? All that potential wealth which is currently held back by corrupt governments and non-progressive cultural habits could be unlocked.

Wait, that happened before and was called colonialism and wasn't good for the natives. But neither is uncontrolled inflow of third worlders into industrialized nations. Is growing global wealth more important than effects on local populations?