Basically, although base intelligence/smartness perhaps has two parameters that make it? Effort and speed. Everyone can put in a bit more effort, but base speed may be baked in, unless one trains it, and max reachable base speed will depend from person to person. Hell if I know, we haven’t really created a definitive definition for intelligence yet.

Edit Addendum: As for what can be considered dumb or smart? I agree, lack of effort can be considered “dumb”. Though the word dumb is a bit broad. I guess we can say many people are, out of habit, “intellectually heedless”

I’m of the opinion that most people aren’t dumb, but rather most don’t put in the requisite intellectual effort to actually reach accurate or precise or nuanced positions and opinions. Like they have the capacity to do so! They’re humans after all, and us humans can be pretty smart. But a brain accustomed to simply taking the path of least resistance is gonna continue to do so until it is forced(hopefully through their own action) to actually do something harder.

Put succinctly: They can think, yet they don’t.

Tbh, I’m more worried about their advances in EUV lithography. Still around 5-10 years away, but still.