I also used to assume it was a field full of highly intelligent people, but when I told this to my cousin who is a doctor he laughed and said something to the e

I also used to assume it was a field full of highly intelligent people, but when I told this to my cousin who is a doctor he laughed and said something to the effect of "The medical profession selects for mediocrity", and went on to point out that being a doctor is a fairly rote profession; most of their work does not involve creative problem solving or critical thinking. It is a very challenging profession in terms of having to learn an enormous body of material, work grueling hours in dangerous and unpleasant environments, and deal with customers who are definitionally unhappy to be your customer. But it's a set of challenges that a fairly wide portion of the population can rise to.