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?
In countries with poor economies, there are problems with overpopulation, this is not the problem. The problem is a corrupt government that does not solve this problem well. Of course, as China, it is possible to strictly limit the number of children in the family, but why? It is better to create conditions under which all this large number of citizens will be involved in the economy, and this can give a strong jump in the economic vector of the country. It's just that the governments of such countries need to provide affordable schools and educational institutions, and then jobs.
I agree with you regarding this, of course, the government has a role in this--the problem of overpopulation and its effects. However, we should not be just focusing there, we cannot deny the fact that the people are also responsible. While the government lacks the support it should be giving to the people, the people are just being too reliant on the government. Both parties have responsibilities to take in order for the problem of overpopulation to be dealt with. No matter how many public schools that provide free education and job fares there are, if the people refuse to make a move then it will be all for nothing. The support should indeed come from the government, as that is the responsibility they have for the people they are governing, but the action of change should also come from the people themselves because if they do not choose to help themselves and continue with their lifestyle of producing kids without knowing what they will do in order to provide the needs of these kids in the future and just hold on to what the government should be doing, nothing will change.
In this case, to solve the problem of overpopulation, the citizens of the country themselves need motivation to change their situation. I mean the motivation to study in schools, institutes, and then the desire to work well, and not to serve time in the workplace. In general, that quality is called engagement. Parents should also impose it on their children, creating strong motivation and, of course, qualities such as good upbringing and kindness. Then the changes will be complete.