Wealth has never been created by geniuses per se. Unless they have two other elements that need to exist.
Extreme motivation, and the opportunity for capitalism.
Most of Africa is controlled by socialist / communist governments, and never in the history of the world has socialism built and promoted wealth.
The countries with the most freedoms, owning property, basic human rights, etc. are the wealthiest nations.
Don't give me "China" either. Per capita they are a third world country. The government controls who has the wealth, and only if it benefits the "state".
If Hawking wants to promote the creation of wealth in Africa, he should be there promoting freedom.
Worked for us over 200 yrs ago.