Apart from the obvious disclaimer that some parts of Africa function much better than others...

Zimbabwe's agricultural sector was wrecked by handing farms to Mugabe loyalists who didn't know what to do with them. His government didn't just go for whites, but also some of the black farm workers who would have known how to use them.

Likewise, the famine in Ethiopia was not helped by either Mengistu's Marxist government (who used Live Aid money for arms) or the previous set up under Emperor Haile Selassie which was based on clientism.