Before Islam they existed, even the Roman built on what was already there in North Africa. Islam destroyed what was there whereever it went, packed the people into caravans of slaves, looted what could be carried off and brought an end to many centuries of careful cultivation to push back the Sahara.
But if you want, in modern times there’s Botswana, a country that really only existed after colonialism because of a railroad. When given independence Botswana had among the lowest per capita incomes in Africa, which is saying something, and had very little in the way of education even among the elites, with one claim saying only one with the equivalent of a high school education.
But their first President had as his heroes and inspirations men like George Washington and Adam Smith rather than Lenin and Marx as was too common in other African countries. He was not a President for Life, didn’t blame white people or colonialism for his country being a ****hole. As a result of this very different ideology than those that went on to make ****holes out of places with great natural wealth to build on the country became one with Liberty, economic progress, placing an importance on education for everyone and so forth.
Botswana did with next to nothing what neighboring states with plenty to go for them failed to do. And they have only their people and not being overrun with Leftists to explain it.
Yes, by American standards the country isn’t “rich” rich to this day, but without the wealth of the world streaming into American coffers after WW2 (when we helped bomb much of the rest of the industrial world into rubble) as they rebuilt America would not be as rich as it is today either.
It isn’t being black that’s the problem with Africa, it’s the ideology of Marx on the one hand and the same ideology about race that insists the color of your skin says something of vital importance about who you are, who you should be on the other. The problem with Africa is the same problem with Venezuela now, the same problem that the Left wants to impose on this country and, incidentally, the same problem that plagues black communities in America once Leftist race radicals became a thing in the 60s and 70s.