This has profound implications in hiring selection. Having exceptionally bright founders could cause a.... founder effect resulting in the entire company being much smarter than average.
Anecdotal, but I know of quite a few wildly successful companies where the founder/CEO still participates in all interviews despite having more than a thousand employees. This seems like a random company quirk but, taking this research to practice, could actually be a large part of why these companies are successful.
[1] In the hyperbolic sense; I wouldn't like to suggest a literal truth here
On the one hand, doctors need to sound authoritative to 99.9% of all people since they are almost always delivering news the patient doesn't want to hear (exercise, eat less junk, take these pills 3 times equally spaced not 2 with lunch, etc.)
On the other hand, many doctors just aren't that smart. Being a doctor today isn't an automatic sign to me that you are in the top 1% of brainpower. Some of my doctors are, most aren't. In addition, many doctors don't continue to learn over time. If you do that, you eventually become dumb.
"Intelligent" people know how much they don't know... "Stupid" or "ignorant" know everything and want you to know it.
Doctors, Mechanics, ... nerds... no one group is immune to this.
https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
"The Dunning–Kruger effect is a cognitive bias in which low-ability individuals suffer from illusory superiority, mistakenly assessing their ability as much higher than it really is. Psychologists David Dunning and Justin Kruger attributed this bias to a metacognitive incapacity, on the part of those with low ability, to recognize their ineptitude and evaluate their competence accurately. Their research also suggests corollaries: high-ability individuals may underestimate their relative competence and may erroneously assume that tasks which are easy for them are also easy for others."