Yeah, before 1970 no one knew what those things were for. "Wow! I've been lugging these puppies around all my life and had no idea!", exclaimed one woman.
"Once, however, breastfeeding, too, was a rarity, until conversations among mothers, supported by medical research and encouragement from doctors, nurses and midwives, pushed it during the 1970s to the mainstream of child-care practices, where it remains today."
Hard to believe someone actually said that.