The answer isn’t simple. You can’t deny that some issues are down to foreign influence. Look at that case recently where a Chinese plant in Ethiopia was poisoning the locals and the water - that’s being directly shat upon by a foreign power. China’s belt and road policy relies on forcing debt servitude on poor countries. Some countries like Sierra Leone have told them to fuck off but most have put on the chains and they will suffer for it.
I wonder as well what the impact of years of horror is. The Belgian Congo was horrific, and I wonder if whole populations can get brutalised to the point it takes many generations to fix. The Congo was also fucked up again by foreign powers with the assassination of Patrice lumumba so that’s probably the best example of country that could be amazing, because both congoes are so rich in resources But people keep fucking it up .
Then Rwanda seems to go against that, and is making some progress in turning into a sane ish country after a genocide. So who knows
Other things are cultural. Some countries are riddled with kleptocracy, you can’t get ahead because every family member will come crawling out of the woodwork and want freebies.
Then there are places like Botswana, which is actually pretty successful.
Culture, not colour, i think is the issue.
adding about wheels. In a country where even modern-ish roads Turn to swamps in the rainy season, I’m not altogether surprised wheels weren’t invented. There are also fewer beasts of burden able to live below the Sahara - tsetse flies make horses a no go, you can’t tame zebras and Cape buffalo are murderous bastards.