I find this to be more than a tad disingenuous. People who are good as opposed to capable in any area tend to like what they are doing. Not many top chefs will have compromised on their career path, they love cooking. Few teachers don’t have a love of kids and learning. Some will become disillusioned as time passes, but most start out with passion and enthusiasm.
We have an extensive catalogue of writers and in close to thirty years I have yet to meet one who did not really want to be a writer- even those who are not continuing to make a high income.
I disagree with you. To maximise your chance of both success and life satisfaction, focus on what you love, what you have a passion for. You can develop the skills, you can become “good” at it. Compromise should only come if there is no avenue to a career that excites and enthuses you. Then you might need to settle on a job rather than a career.
As you stated, some people are unrealistic with regard to the realities of some careers, they like the concept with little awareness of the process. This also happens in other areas of life. Some people love the idea of being in love, rather than loving another person. Some women love the idea of motherhood with little concept of the dedication required to raise children.
PS — MANY Doctors do not have a high IQ. It is not required. Determination is required.