[watwut]

It was making training army difficult for American troops for example. Soldiers complained about it.

Such high illiteracy rates will make it impossible to build enough of management and general bureaucracy needed to build anything large. It will make it hard to train workers in technology. You won't build railroads nor roads, you won't mainten them either.

Primitive mines are not competitive. They are not producing enough to feed you. And hungry people won't save money for school. You need technology.