to be a powerful country it does not mean you have to have developed economy , or high population ,
one of the conditions to be a powerful country is to keep weak ones in check , because it makes your Foreign relations stronger ,
Did you ever hear of Hosni Mubarak. According to my research he is a bad leader or Egypt. The US helped Egypt by giving them 2 billion. They spent 1.3 billion on military (smart). And .7 billion went into his pockets and the pockets of other government people. Also if you were to help them they might take advantage of you and stop working hard if you are helping them. They might lazy out and not do a good job.
i will differentiate between exploitation and keeping in check positively , it is one of the responsibilities of the powerful countries to keep weak ones in check for three reasons ,
first point is , some countries have economical problems that maybe will help the government or the citizens , for instance , bangladesh or pakistan where peolple there does not have the day's food