I can see people not wanting that second promotion. It sounds like it would be at least partly a different job, requiring orthogonal skills like you mentioned. I would imagine one can stay a welder and improve to a point where they would earn even more than site managers.
Like, there's welders that can weld garden gates, then there's welders that can work on underwater pipes, then I imagine organizations like NASA need even further skilled welders. I don't think there's ever a need to transition to managing subordinates.
A career can move horizontally or vertically. What most people forget is that "moving up the ladder" isn't a promotion: it's a fundamental career change that requires vastly different skills.
Being a fine engineer or technician doesn't make you fit for a leadership position where people skills make all the difference. And once you're in such a role, your operational experience will go stale after a while since you can't spend vast amounts of time deep diving in concrete technical problems. Your job is to manage the overall picture and delegate.
Here's a nice blogpost from Charity Majors (Honeycomb) about this exact conundrum:
The crux to this is that it's actually fine to not climb the ladder. Like you said, you can perfectly hone your skills over years, establish a name for yourself and become a specialist who gets paid more then their boss
Doing that still requires a due acumen to manage your own career as if it were a personal business. Which means scouting for opportunities that help you earn more while allowing you to work on new challenging projects that help you expand your technical experience. Hence why hopping jobs isn't necessarily a bad thing for your career.
Of course, that's not what employers want or need. That's why they play the loyalty or career card. And why this myth "climbing the ladder is a good thing" persists.
Let's not forget, most people stick to their jobs not because they are particularly fond of their jobs, but because of household debt (children, car, house, student loans,...) or because there simply aren't attractive alternatives close by and moving / migrating is too expensive (emotionally, culturally, socially,...).
Finally, office politics and workplace culture are an aggregate and a compound sum, not just of organizational policies, but also of what employees bring to the table, where they are individually in their lives, what they need now and in the future, and which cost opportunity trade offs they are willing / choosing to make.
>there's welders that can weld garden gates, then there's welders that can work on underwater pipes
Like any other blue collar skill welders are primarily compensated for the skill/experience required to do their job and the amount of inconvenience, discomfort and/or danger that comes from the setting in which their job takes place
Welding fancy alloys for pressure vessels takes more skill and is therefore compensated better. Welding together railings is much easier with much looser quality control so it's not compensated as well because more people can do it.
Doing either of those things in a heated and air conditioned shop is going to pay a complete pittance compared to doing them in the mud in the middle of nowhere, underwater, in a confined space or an otherwise physically demanding and/or dangerous environment.
Like, there's welders that can weld garden gates, then there's welders that can work on underwater pipes, then I imagine organizations like NASA need even further skilled welders. I don't think there's ever a need to transition to managing subordinates.