Another aspect of the birth control part is that women can control their fertility through their teens, and then through their 20s, and then through their 30s, and so on. Many of them do so until children make sense financially (as in your case), but there’s a subgroup there who will delay and delay and delay long enough to ask themselves, “Wait, do I really want children?” Very few women have had that opportunity during the history of our species, and there’s a significant number of them who honestly assess it and make the decision not to. My wife is one of them. She was 100% on the “I want to be a mom” train as a teenager and college student, but as she explored the world and learned to live on her own she got the chance to deeply reflect about why she wanted to be a mom, and the reasons just didn’t line up. Birth control really is a game changer because it puts the power of fertility squarely in the woman’s hands for the first time really ever. Before now procreation depended entirely on the influence and whims of men.