You're forgetting the part where the Europeans set the society up specifically so that it would fall apart if they left. There's a reason why damn near every African thinker of the mid to late 20th century went to the same university, and it isn't because that university was particularly good.

It was the only university that accepted blacks.

You can certainly say that many of the post-liberation African states made a huge mistake when they decided to drive out the (white) people with the technical expertise to keep the nations going, but you can't blame those states for the situation that they inherited. The Europeans came, took everything of value that they could find, set the society up to collapse if they left, and then left.

Now they're laughing about it on the other side of the world, on top of the horde of non-renewable resources that they stole.