Especially as the population is increasing all over the world, we cannot throw away the old people as people are born and die. I couldn't agree more with you, the birth control rate every citizen should keep in mind. One to two children is enough especially one boy and one girl is a happy family. But the population in the world is increasing so much that the care of the elderly has decreased, but we cannot neglect the elderly. Because I will also grow old one day (that's why every people should be given equal rights) such dilemma cannot be created in the family.
Many of these countries which are under developed are not even doing anything or trying to run a sensor that would count and know their actual population. I think sometimes, these are caused due to corruption embezzlement of government funds for personal luxury.