What most people think of as being "really smart" is polymaths. These are people that suck up knowledge from many fields and make novel connections. It is believed that they are extremely rare. Some even argue they don't exist

Modern academia focuses on a high degree of specialization which excludes most polymaths. So we have specialists that are highly intelligent in their narrow field of expertise but ignorant in most everything else. The bulk of the "smart" 1% are these types of people.

I think it's important to understand that a role does not equate to intelligence. There is a spread of intelligence in all of society and in all roles.

Look at medickne: there are 10s of thousands of doctors but they are not selected for "intelligence". Sure, passing high school exams is part of it but those are often biased towards memory. But other parts of selection are around social biases through interviews, university selection processes at. Also in places like the US selection is based around wealth - you're more likely to get a place in a medical school. If you can fund it versus not.

So already you have a mix of intelligence in the field. Then within that you will have intelligent people and idiots. Someone had to place last in their medical school year, and someone had to be the worst in the entire years cohort across all medical schools.

I'm a doctor and I've met plenty of doctors who are fucking idiots frankly. People who sail through exams because of good memories for example - they are not intelligent. Intelligence is more than that - problem solving, creativity etc - but memory is mostly what we test for because it's easy and lazy way to test students. The other elements of being a doctor are taught but not tested well - instead people gravitate to sub specialties that rely on specific skills beyond memory.

Being a doctor or an engineer or a dentist does not automatically mean you are intelligent. Our whole society is geared around lazy testing and metrics of academic success, and there are also other elements to those jobs where you can succeed regardless of intelligence (for example how much intelligence does it take to extract a tooth? Or take out an appendix 100 times?). You can succeed in these careers without high intelligence. That is not to say doctors are stupid either (the upper quality of medical practitioners can be incredible), just that the minimum standard is lower than people imagine.

And for me personally the brightest person I ever knew works in advertising. I've met a lot of very intelligent people in Medicine but also a lot of idiots. I've met a lot of intelligent people in scientific research fields, but also in computing and business and through family etc. Job titles are not a good metric alone - a blunt but flawed metric at best.

Re the first : I wouldn't call those guys smart. I'd call them specialists.

Re the second : well yes, the truly smart guy would be aware of the limits of his understanding.