PhD involves years of thinking very specifically about an extremely narrow set of problems, not building a robust set of reliable heuristics about how the world outside of that field works.

I know plenty of brilliant PhDs and Physicians who couldn't real-world their way out of a paper bag. They're dumb as a rock when it comes to anything outside of their field, because their field has vacuumed up all of their mental energy over the decades.

By comparison, I'm pretty mediocre at what I do because I read widely, follow the news, and have elaborate political discussions for fun. By their standard, I'm dumb as a rock because I'm up late reading about the Soviets in Afghanistan, instead of yet another journal article.

Time is finite, and it's all a big compromise.

I wouldn't say that. There are different kinds of "smart", and then there is "poor analytical skills". There are "smart" people, for many values of "smart", that still have such poor analytical skills that they think Covid is fake, the earth is flat, bigfoot is real, Elvis is alive, etc. Just calling them 'dumb' doesn't get to root cause.

Pretty much this.