A naturally-born baby is an emerging health crisis. The negative outcomes stretch all the way to neonatal and maternal death. The timeframe can be a dozen minutes to dozens of hours. Treatment is an unknown and emergent process involving many different specialists whose schedules are effectively locked down for the duration of labor.
A c-section baby is a surgical procedure that you can plug directly into Outlook. It is entirely managed by the medical team with zero input or influence from the patient. It is routine, it is repeatable, it is entirely divorced from the natural complications of birthing an infant naturally and consistently too large for a mother's hips.
This is a really common number that nobody likes to talk about the source of. We like to say that 80% of women are perfectly capable of having an unassisted childbirth without any external help whatsoever - because prior to the advent of modern medicine, the infant mortality rate was around 20%. So - control for "modern medicine" and around one in five women is going to need some sort of medical intervention. That it's gone from around 15% to around 30% has a lot more to do with liability and scheduling than it does with "money."