Again, that is already present in plenty of (unsure if most) developing countries, and the ones where it isn’t aren’t common sources of brain drain. There’s a reason the West tends to import Indians and Iranians rather than, say, Congolese; the majority of educated people from any country will stay there, either because they don’t want to leave or because they can’t find an opportunity to do so. This is simply not the bottleneck holding back the Global South; education is one of the few things a developing country can do more of with minimal effort.