> Fair enough, but in a way it's more false comparisons; investing billions into a tribal-agrarian society in the midst of civil and religious war is qualitatively different from investing it into an already industrialized society.

Not necessarily. If you ignore the (in reality rather important) "ongoing war" aspect, investing in more backward region should give you better return on investment, not worse. That's because investment, like anything else, suffers from diminishing returns. In backward regions, there are a lot of low-hanging fruits to pick, and small amount of money can go very long way. That's why all the NGOs are talking about microlending etc: even trivial amounts of capital make a huge difference.