There is no doubt that in Africa the number of people living in abject poverty has decreased. Access to basic health care has improved as have other measures used to assess the quality of life. Nevertheless, speaking from the perspective of an African born and raised in Africa, I would suggest that the reaction of the great majority of the inhabitants of this continent, when informed that the stats shows significant improvements to quality of life, would be to refer to that Oscar Wilde quote about there being lies, damn lies and statistics.
So what you are saying is that most Africans do not have a grasp of what life is and was like on their own continent, the implication being that, despite things being better, they don't think so.
Also, I'm not familiar with Oscar Wilde's quote about lies, damned lies and statistics. Could you tell us what it is? I am familiar with Mark Twain's quote (that he attributed to Disraeli) and that quote is a bit of a millstone as it is used far too often to dismiss true statistical facts.