As for your comment on C Sections: They are common for two reasons.
One, the main reason is because babies are larger nowadays and won't deliver easily, and prolonged labor can result in brain damage and a large lawsuit against the doctor.
Two: more high risk moms who are older (i.e. over 35) are delivering babies and often CSection is needed since even normal labor will cause fetal distress, or sometimes because you might want to deliver earlier to prevent complications of toxemia or diabetes.
Are there biological advantages to baby for vaginal birth?