Building a fibre network that connects cities and countries together, from enterprises sites to data centres, and sometimes all the way to homes, is not that hard, even in Africa. Plenty of contractors can be found with either lots of cheap workers (shovels and spikes) and machinery. Managing the quality of the build is tricky, as contractors continuously cut corners (usually they don't dig to the 1.2m depth one would require) so we need to be on their back all the time. Finding equipment, material (fibre, manholes, poles, etc) is straightforward and can be imported if necessary. Local management can handle this alright.
Where it breaks, literally, is to maintain the infrastructure. Any shortcoming in the quality of the build will very quickly show, e.g. manholes not at the right place, shallow dig will get fibre to show and be broken, poor quality poles will break, etc. Reliable networks are not break-free. Good networks will see a break every 300km every month in Africa context. So well managed maintenance teams need to be around, equiped with vehicles, spares, tools, and located at critical points (not too far from any point). Roads can be bad (or absent, so think motorcycles), police/other forces can bar roads, wild animals can present a significant danger at night. A 4h turn-around time (from time of detection to resplice) is critical to call the network "reliable". Of course, fibre networks must be meshed, with at least three routes between any point (i.e. any significant town must see three fibre routes on the map).
Once set up, the networks can be commercialised. Interconnections must be managed and accounted for (inventory management) and quality managed (forget about opening your manholes to any CSP team without chaperons). The best set up can be ruined quickly. Networks are expensive to build ($25-30/m is a good benchmark) and infamously expensive to maintain and commercialise. Pricing must be managed. We have seen a move by larger players to pay up-front for a proportion of the build cost, with very small ongoing payments. This won't support any form of maintenance, and fibre owners will eventually subsidise their large customers in this scenario.