People lower than that in the org structure in corporate jobs, or people in hourly positions/unemployed may not have the money to fix their teeth, but yeah, no one expects that shit from people in those positions. The people I feel bad for are people who've suffered tooth loss because of poor dental care as kids. Some people have smiles that are waaaaay more fucked up than can be easily disguised.
Once knew a low to mid level professional colleague who never, and I mean NEVER, smiled. Realized he was talking in a way that covered up his teeth, and once I knew that, I noticed he was missing about half his teeth. His job had meh insurance and there wouldn't be much way to fix that shit for a reasonable price short of taking your chances in a "medical tourism" country. I can't imagine how much he had to change his normal behavior/habits to keep people from seeing his fucked up mouth, but there's no way anyone would have taken him seriously if it was obvious he had the dentition of an Appalachian hick.
There'd be more value in this kind of article if it was like "don't totally disrespect someone for having a really jacked-up smile, did you know it could cost as much as a new car to fix that shit?" instead of pretending that normal people with everyday jobs need to live up to a perfect standard. "Some people are really far outside the norm and are still good/smart/competent people" is an ok moral. Creating some sort of "stop demanding perfection" strawman so EF readers can feel smugly superior when they deign to allow someone with slightly crooked teeth into their group of friends isn't a very ok moral, but is very par for the course.