Why with all this aid do conditions remain the same?
The aid is channelled through inefficient and too often seriously corrupt governments. Most areas with infrastructure sufficient to effectively distribute aid don't need it in the first place.
Why does this Continent remain so primeval?
It isn't, actually. While 38% of the North American continent is wilderness, only 28% of Africa is. It isn't a case of too much jungle, not enough people, it's too many people, not enough wealth and especially education.
Who is helping the most to make a difference? Nugent or Bono?
Well, I dunno, "teach a man to fish" and all that...OTOH, Bono is eminently edible...
Build a man a fire, and keep him warm for a day.
Set a man on fire, and keep him warm for the rest of his life...