Bull.
Europe was a thick huge forest during antiquity n the early middle ages, by clearing it people prospered.
Black Africans didn't develop because they didn't face harsh weather conditions
Those who left Africa had to adapt, those who failed died like flies...only the cunning survived, and once mastering the environment had aquired the skill sets to create civilization.
A harsh climate in Africa is Egypt, practically everyone lives along the Nile. They had to adapt and learn how to make the most of the environment and the river to prosper.
Black Africa however...is green, endless Summer, you loose ur food source? No problem, just walk a little n start to pick whatever you want...
Africans didn't develop because they weren't spurred, they became lethargic
while the outside world contested with each other for resources which led them to create invention upon invention..