It's kinda complicated, the point of a business is to make as much profit as possible. There are lots of issues in Africa, I don't think making African servers is gonna have a good return on investment (No popular online game has an African server btw, not just riot).
There are electricity issues, we don't have power supply 24/7.
Financial issues, the minimum monthly wage of some African countries, like where I'm from, can't even purchase a glitchpop dagger, and lots of people don't even make up to that wage in a month, so it's rare to see folks with gaming PCs around.

I get 140-150ms on London server, from west Africa. I just laugh anytime people tell me I have an advantage with it.

We have internet in Africa, it's servers we don't have