Women get c-sections for a lot of different reasons. If the baby is in the wrong position, if there's a health condition with either mom or baby they may schedule a c-section a little bit early. Placenta Previa is another reason to get a c-section. Also if you have had a c-section in the past, most doctors will only allow you to do a c-section for all future births. The muscles weaken and it can become unsafe. However, lately, a lot of doctors are willing to allow women to try a vaginal birth after a c-section these days but I think the pregnancies have to be so far apart.
Also....let's face it....some women are control freaks and wan to know exactly when they will have their baby XD
I personally am trying to avoid a c-section at all costs, however, between problems with psoriasis and my placenta is currently very low, I might have to if that doesn't change.