Advanced civilization needs clothing and tool making. And the need for strong buildings which can be secured from cold and from predators. Africa at the equator is just too warm. No need for clothing. No need to adapt.
One other idea about civilization else where. Africa at the equator had long periods of drought. One cannot adapt to eating sand. Zero rain means zero vegetation and zero game animals. Therefore the humanoid life forms had to leave in order to survive. Colder weather climates had snow melt and game animals which would drink from the snow melt waters.