You do not become advanced by being isolated. America got advanced math from Germany. Tesla came from Eastern Europe, you need institutions of higher learning, and we have professors and educators from around the world. It isn’t that the people aren’t smart, it is just the governments are corrupt. This does remind me of the black exploitation films of the 70’s etc.
Well, actually...
Low IQ is common in tribal communities that intermarry. Africa, Middle East, Latin American Tribes...
It's even continuing here, in the US, where ghetto denizens are breeding without knowing (or caring) that they are first cousins, half-siblings, or even father and daughter.
Low-IQ societies don't produce forward-thinking leaders.