I'd say a lack of education and corruption. A self centered view of the world creates wealth for few and leaves many behind.
I think its also something historicall as many countries have been exploited and have often been left alone to repair the damages themselves which they were not able to handle.
I agree with you. It is because of people's selfish desires. especially when he/she is in the government they are blinded of what's really happening outside their world.