To invest, you literally have to come in with a security team / truckload of weapons or someone is paid (Wagner / Chinese government) to do it. The invested operation has to be vertically integrated with hand-picked assets, human resources, and supply chain. Very difficult situation to do in a way where the general populace benefits. In cases like Zimbabwe where farmers came in and did sustained investment, it did work having the tribal populace as helping hands but as soon as the reigns were handed over they immediately gutted everything and it went to shit followed by hyperinflation and mass starvation.

Very difficult problem that no one has really figured out. Kenya and Rwanda some of the more interesting leading edges in sub-saharan mainland africa as far as economics are looking.