I believe the answer is: Neglects internal conditions of Third World countries that inhibit economic development
In the dependency theory, it stated that the flow of resources in the world will always move from underdeveloped nations to the more developed nations and only enrich the developed nations.
One weakness of this theory is that it failed to consider the internal conditions such as political instability, lack of education, or tyrranical rulers that might cause people in third world country unable to utilize their resources.