https://en.wikipedia.org/wiki/Jason_Njoku
I guess they target Africans in the diaspora, who have much more disposable income.
It is very tough to succeed targeting Africans in Africa without first focusing on a specific country.
By the way, I see this phenomenon a lot with African restaurants in the US. If you are targeting, say just Nigerians or Kenyans, your restaurant will fail 100%.
They are not enough of them and are often unappreciative and judgemental--complaining it is not like their mother's cooking!
The African restaurants that succeed make it exotic and exciting enough to appeal to Americans and the broader populace. They may invent dishes or create a 'fusion' menu but who cares! After all, there is no "General Tso's" chicken in China!