Insanely corrupt nonwithstanding, from the outside my impression of Nigeria’s government was always that they’re smart enough to not saw at the branch they’re sitting on. Hence also the comparatively good education system: Embezzling funding there might be quite profitable, but it’s even more profitable to have at least half-way educated people run an at least half-way developed economy and then embezzling funds from there. It’s much more profitable to steal the harvest than it is to steal the seeds. Compare with South Africa and their electricity grid.