I qualify for Mensa, but never bothered.
I know a guy who does Mensa get togethers, and my observation correlates with yours.
Most smart people are in jobs where they have lots of other very smart people to talk with.
Most Mensa people are smart but dysfunctional.
I know a pretty intelligent guy who was in a job that required him to make use of subject reference works that featured concepts named after his boss.
Yep, one of my esteemed parents joined Mensa, long ago, and went to some get-togethers in Manhattan, where you could meet the cream of the crop. People like Asimov, people celebrated for brains. Verdict: “They stuck to the same subjects as anyone else: food, work, and sex, in that order.”
Me, I hang out with my neighbors, they are mostly elderly folk who need rides or other such assistance. They are not, as far as I can tell, Mensa material, but I learn from them all the time and they are never boring.