Besides, have you tried to learn a new natural language in adulthood? A bootcamp won’t get you far. And natural languages are really forgiving in comparison because you’re communicating with a human-level intelligence that’s used to inferring meaning from low-bandwidth ambiguous datastream.
Yes, most definitely.
Is it reasonable to assume some people will land on the far lefthand side of certain bell-curve-fitting measurables, or unmeasurables, that lends them to being not particularly well suited for certain kinds of activities?
As long as people can practically attract a mate while lacking this sort of abstract reasoning ability, the majority of the population won't have it.
I've read that people tend to be intimately attracted to people of roughly the same intelligence and socioeconomic background, for whatever definition of intelligence was used.
Having said that, some people do turn out to become engineers fabricators artists and build amazing things. You're probably right though, the majority of the population probably don't have it.