Evolution got around that by birthing what are essentially still fetuses compared to most other non-marsupial mammalian newborns and then continuing the base development process of the brain after birth. See how a lot of other newborn animals are already walking around just minutes after being born.
Yeah. If there's an evolutionary aspect to the increase, we should expect to see c-sections as a generational phenomena, and correlated with cranium size. I wonder if that study has been done.
I admittedly havent spent much time thinking about the problem, but it seems to me that the issue of getting one human out of another human is quite a difficult problem to solve.