It is true that developed countries have often get to this point where it may be reasonable for society so support child-rearing for stability reasons. But they often still have much more people than say hundred years ago.

But note that this situation is relatively new, while natality was praised even during times where population was expanding. My point in this thread is that natality is not intristically good (or bad) value and it is for country to decide on which level want to motivate individuals to change their behavior, but having a child is still fundamentally individual decision.