I don't get the 'too posh to push' women, vaginal birth is easier to recover from and a c-section leaves a scar, it should only be used when vaginal birth isn't an option and not to facilitate giving birth to a timetable.
I think the "too posh to push" thing is a little overstated-- I just can't imagine any reason to have a scheduled c-section unless you've already given birth that way once and don't want to risk a vaginal birth after cesaerean (VBAC). I have known maybe one woman who wanted everything on a schedule so much that she elected to have her child via c-section from the very beginning. I also know of a woman who had a cosmetic surgeon present at her delivery so she could get a tummy tuck at the same time, which does make some sense. But of all the women I know with children, that's only two in at least a hundred that I know.
Another reason for it is that if a woman knows she wants to have a tubal ligation after a pregnancy it may be just as easy to have the child via c-section and get snipped right there.
It's an interesting phenomenon, but like I said, I think it's somewhat overstated. Most c-sections are decided during labor and delivery by a doctor. Whether doctors suggest c-sections too much is another topic altogether.