well, when you can pay somebody half the price to do it in vietnam...
this is going to eventually hit a brick wall, but africa's a big place.
i've been saying for years that we need international worker solidarity. this is how they beat us on nafta - they got us to see mexico as a competitor, rather than as an ally. and, every moment that we take this competition for granted is a moment they will continue to defeat us in. india just pulled out of a major trade agreement at the last minute, but it's the same basic economics at play; india is outsourcing it's jobs to lower-income workers in vietnam and cambodia, who are that much less along the development scale. and, a broad level of international solidarity is what is needed to throw a wrench in it. they will try to foster competition, instead.
at some point, you run out of workers to exploit, unless you make the thing cyclical, i guess. that's too much foresight. and, i shouldn't give them ideas.