Your arguments about zero-growth equilibrium only apply in a world of constant resource availability but it is clear that many resources are peaking or already in decline - so where will Africa get the resources to grow when other nations want them so badly (and tend not to care how they get them).

Let's look at your other argument - (massive population growth) leads to lots of hungry younger people leads to motivation to work leads to economic growth. Brilliant! Now if we can only starve some Europeans we could get economic growth there too. Maybe tell this argument to the workers shot dead at SA's platinum mine recently. No pay rise for decades and when you protest its bullets for breakfast.

Correction Michael,
When you try to outflank a nervous, poorly trained squad of African Police with a view to killing them with machetes and mutilating their bodies you end up being shot dead, every time these Black Police go out on a job these days they must be thinking "Remember Cato Manor".