You need a lot of stuff in Africa before data centers become a priority...
That is true
Better to run long line fibre optics than consume scarce power. When cheap reliable power and aircon is ubiquitous O hospitals and morgues and pharmacies it's time to have a local DC
Need stable electricity in most of the countries
And infrastructure in general. And for that: governmental stability and continuity. Nobody wants to invest into building infrastructure when they can't be reasonably sure that they can still work there in five years.