It might be explained by what is know as Yerkes–Dodson law[1], which describes how performance increases with mental arousal up to a certain point then decreases. If different types of tasks correspond with different arousal for different people, then the type of welder or developer one is is orthogonal to their fundamental skill. Instead it would mean that the first type needs to cast the problem as something novel in order to gin up the necessary level of concentration to get the problem done, hence the rock solid code that has sloppy/inconsistent style.
It makes sense that a good advocate would be highly skilled, but the type who has difficulty with necessary work that seems mundane. In other workplaces this might be the person who seems to have low output, but gets their coworkers past their roadblocks.
For tech, I usually remember it as AmaGooBookSoft - Amazon, Google, Facebook and Microsoft. Apple is sort of a hardware company so sometimes it is included and sometimes it is not.
His subsequent (and current) job is now as a very well-known expert as as developer advocate for one of the big four tech companies.
You'd be surprised at what you find developers out there doing, the only good metric on a person being a good developer is writing fundamentally sound code. Literally nothing else matters.