Birth control also coincided with a very deliberate push to get women in the work force at scale. In retrospect, it was obvious that doing this would cause fertility rates to decrease regardless of the popularity of birth control. My wife would absolutely love to quit her job and stay at home full time, but it's hard (note quite impossible, but very very hard) to actually do this today. All her friends with kids want to do it too. Obviously I wasn't around back in the mid-1900s, but I do wonder from time to time if people actually understood that this was the trade off we were all making in changing the culture like we did.