How do you think these developed nations will fill vacancies in their nations and get cheap labor if the population of these developing nations is reduced?
Even the most populated countries like China, India, and others have already developed, and they are still creating other things that will make their citizens enjoy their way of leaving. To me, overpopulation cannot affect the development of a country if the government in such a country is doing well, but in a situation where the government is corrupt, they don’t care about their citizens.
You can see that even if there are resources available, they don’t care to make use of these resources in such a way that they create job opportunities for the citizens, and I believe job opportunities are one of the ways that we can say a country is developing when everybody is working. And that is what the Chinese government is still doing. With their very large population, are we going to say they did not develop? Nah, mate, so if a government uses available resources in a nation to create other ways of earning, there will be no poverty.
You have a good point here regarding job opportunities. Big population means bigger manpower for a country. However, if the government of that country fails to see that and makes the best out of it then it is possible for them to only see overpopulation as a negative thing. Take this country I live in for example, there are a lot of people and yet we lack workers due to individuals choosing to move overseas for better job opportunities that offers higher salary, compensation, and benefits. If these workers were able to find that here in the country then we wouldn't be lacking educators, doctors, and other professionals. This example shows just how a lot of country's government fail to see how they could use overpopulation to their advantage if they can only focus on the needs of their people.