It is strange that they still steal despite those salaries. There should be the death penalty for that kind of stupid behavior.

But I believe a/the biggest problem is the birth rate. 50 years ago in Subsahara Africa lived around 150m people. Today it's a billion. If back then the population had remained stable, today the average African would be about 7 times as wealthy. That means, an average income of about 15-20k $ per person and year. So, get the population growth under control and you'll grow wealthy as everyone else is and like China managed to do.

But then again, it's Africa. Not sure if you have the leaders who can help to facilitate this kind of transition. Nonetheless, I hope the best!