If that person didn’t know better, they’d develop an inferiority complex and spend the better part of their life bitter and assuming themselves to be failures. They didn’t get to do what they thought they loved, so they haven’t actualized their lives as they were supposed to.
You’re Not Meant to Do What You Love
Brianna Wiest

A great perspective, yet I think this article is painting the picture with a too broad a brush.

Continuing with your example, iQ might not be the best measure of person’s suitability to be a good doctor anyway. And which of the many iQs are we talking here?

Also, Medicine is a vast and diverse profession able to accommodate all sorts of people types from sleek types with an eye for beauty and design to high iQ and precise neurosurgeons to super emphatic and socially oriented GPs.

Also, even if this given doctor would in fact have a lower iQ than average, this might just mean his learning pace might be slower. His passion might help to sustain his love for his chosen field over a long period. That’s a good thing. Especially if he/she can’t imagine doing or wanting to do anything else in substitute.

I’ve know people who started being naturally skilled at one thing (math or chemistry in my case), who have grown more fond of other fields, even though they were not ‘naturaly skilled at’ at these new pursuits to begin with.

I’m just optimistic when it comes to adaptability of humans more than trusting such narrow measures as an standard iQ test.