haven't watched the video but it's probably several factors. like on a fundamental level if you don't have contact with people living in different environments, coming up with their own ideas on how to survive and prosper, and share those then you're going to be behind. europe had the whole bronze tool trade and more going on, like copper coming from kazakhstan going to turkey and making it's way all over europe into the furthest north of scandinavia. africa didn't have that because of some fly carrying a parasites killed all the cattle and horses, so no beast to carry burden, no need for carts, no need for roads, less trade, less sharing of ideas. you're behind. and that's just one part of the factors.
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