Why is Nigerian and South African music so popular?

Afrobeats and Amapiano are two of the most popular genres in Africa and both genres are now also being recognised and appreciated worldwide. This year's prestigious Grammy awards gave us 'Best African Music Performance’ for the first time. Out of the seven nominees- four were from Nigeria- Davido, Burna Boy, Asake and Olamide and there were two artists from South Africa, Musa Keys and the winner Tyla. The only other country represented was Arya Starr from Benin but even she lives in Nigeria. A lot of people raised the question of why this award didn’t recognise artists from other parts of Africa if it's an award created to celebrate music across the whole continent. So why does Nigerian and South African music seem to be dominating music from other parts of Africa? Guests: MC Yallah, ePianoh and Keiitumetse Maako