Expanding on this further, the reasons that baby formula is so prevalent follows the exact same pattern as just about everything else wrong with American diets and medicine.
Formula manufacturers pushed doctors and hospitals to introduce it to women AS SOON AS POSSIBLE because the only thing that gets women to produce more milk is more breast feeding and having an out that can make the baby stop crying for a little while to let the mom sleep is right there.
The only surefire way to increase a woman's milk supply is to keep responding to the baby and trying to feed when they're hungry. So by reaching for the formula, women don't end up developing more production and suddenly you're relying on the formula to keep the baby fed. Breast milk starts to reduce so the mother supplements more formula until that's all the baby can eat because the mom's milk is bone dry now.
This hits first time mom's the hardest who are developing the plumbing to make breast milk for the first time. It's insidious. There are LOADS of health benefits provided by doing the act of breast feeding for both the mother and child that get lost out on by having formula within arms reach at the very birth of the child.