Okay coming in late to this debate but here's my opinion. If there was no formula then the majority of people would breastfeed, we'd all be more educated and have more social and medical support with it, people in third world countries would not be conned in to using formula, many babies would be healthier, PND rates would likely lower, co-sleeping and the use of baby carriers would likely increase, breast cancer rates would perhaps be lower, nursing in public would be normal, as would nursing toddlers and children. It's very likely that drugs to increase supply would become far cheaper and more available, perhaps with medication to stimulate supply in women who could not produce any milk would become available. Maternity leave in most countries would have to be extended to allow for a minimum of one year nursing on demand.
Then there would be children who starve to death, children who's mothers have had enough and supplement with normal milk, water, rice... Anything, because they're exhausted and in agony and alone and they have no idea what to do. There will be mothers who simply don't want to breastfeed and take the advice of friends and simply give normal milk because that's the only alternative. There would women who feel helpless because they want or need to work but cannot because they need to nurse. There would be a massive decrease in people adopting babies who are not rich enough to appoint a wet nurse or buy donor milk. Not to mention how on earth children in foster care would manage. The billions of abandoned orphans in third world countries would starve or become very ill. Society would return to the idea of women as women and men as men, forget stay at home dads, and god forbid two gay men adopt a child.
The answer is not no formula, it's knowledge, support, and the responsible promotion of formula only when it is needed. People also need to accept that despite everything, some people choose to formula feed, and that's okay.