Why are African teams not doing well?

African teams have only won 1 out of 11 games so far. They have collectively scored just 5 goals (and 2 of those were on penalty kicks). Nigeria and Cameroon have already been eliminated, and South Africa and Algeria have almost no chance of advancing to the round of 16. Even Ghana will likely need to not lose against Germany to move on. A lot of people thought this was the year an African team finally reached the semifinals, but the South African setting doesn't seem to be giving the African teams much of an advantage. Cameroon has been the biggest disappointment. They blew so many good chances today! I'm hoping Ghana and Ivory Coast are able to get into the next round, and then maybe the crowds will really start to get behing them.