Raising babies takes a tremendous amount of infrastructure. An adult human is mostly self-sufficient; babies are not. As somebody said, it really does "take a village" to raise a child.
Reality check: Children have grown up all over the planet for all of history with no infrastructure with poorer parents often raising half a dozen of them. The way we raise western 21st century kids means most parents have enough with a few, but unless they quite literally die they grow up every other way too. The "takes a village" saying is about society's influence, everybody wants to fit in with their peers and prevailing norms, even if that is at odds with your parents.