Have you been to Rwanda? It is a land-locked country surrounded by countries with terrible road infrastructure and corrupt border crossings. It costs more to get a container from Dar to Kigali than it does to get a container from China to Dar.
Rwanda is unlikely to ever become a place where physical goods are manufactured at scale: it costs too much to import raw materials and too much to export finished products even if you can get all the raw materials locally. You can sell into the local market, but it is a very small one.
It is an interesting place to be if you want to work on some kind of knowledge product, ie, software or services, micro-work etc, but even then it comes with its own set of challenges, it is no slam dunk.
Source: I lived there for over four years and cofounded a small software company there (http://nyaruka.com), which eventually built TextIt. (https://textit.in)