I’ll second this. I’ve seen this with researchers, engineers in a variety of fields, construction supervisors, someone who overaw manufacture of nuclear test equipment, a handyman who makes stuff on an old fashioned loom as one of their many side-gigs, cpas, tech workers of all different stripes, commodities traders.

Any job that even somewhat relies on knowledge can get this way, if the person working it puts effort in and takes pride in what they do. The apparent complexity or prestige from the outside has little to do with it.