A close look at this situation shows that many of these overpopulated nations mostly in Africa and Asia are underdeveloped. While these underpopulated nations are economically buoyant. I think the reason for the poverty of these developing nations is not the population but bad governance and the inability to maximize and distribute available resources equally. We cannot deny the fact that these overpopulated nations are economically important to these developed nations in terms of human resources. And they contribute immensely to the development of these first-world nations in terms of cheap labour.
Possible can be included with the management of the government sometimes, even a good developing country from the previous management can easily manage the growth of an economy but of course not all through years they are the ones who handle the community, and the next administration doesn't really care about the community just for the money itself this can be possible makes the people suffer because of this wrong decision made by them. The reason why getting wise to vote is ideal and just known only.
Too much population too can affect the economy and if the parents are not capable of supporting the basic needs of their children and this cycle as always happened and the government is not prepared with this case reason why they didn't give all the support needed by those people. AFAIK in some country there a restriction with the limit of possible children they have.