I think he's talking about the skill level, defined roughly as how much background knowledge you need to perform the job + how much judgment & concentration + how much creative/analytical thought.
This doesn't necessarily correlate with either remuneration or work environment. There are plumbers in the Bay Area who make more than a theoretical physics post-doc and deal with a lot less stress, but most people would agree that getting a Ph.D in theoretical physics requires more skill than becoming a plumber.
I don't think plumber vs. theoretical physics post-doc is a great example.
Plumbing is critical skilled work, taking years to master, and is paid accordingly.
I imagine plumbing is also very stressful, at times, such as when you're being careful not to flood a building, or avoiding breaking something that would require ripping open a floor to fix.
Though plumbing guild training sounds not entirely different than academia. (And postdocs tend to get paid poo because the market, and their guild, permit it.)
This discussion is nonsensical. If a theoretical physicist is so over-educated that he can figure out how to parlay his skills and knowledge into a $200K+ job in Quant Phynance, insurance, or as a full-fledged Data Scientist, then he/she needs to reskill on street smarts.
It's not all about getting paid the most for some people. I think a challenge for the case of physicists that want to work in that field is that there are more of them than are jobs.
Compare to programmers (of all levels), where there is basically endless demand in most big cities, and in the top say 15 tech centers in the us probably a few 100k jobs are available in total. I'm sure Seattle has 50k jobs.
It is interesting how the trade profession system of apprentices, journeymen, and masters resembles that of the academic system of grad students, postdocs, and PIs.
This doesn't necessarily correlate with either remuneration or work environment. There are plumbers in the Bay Area who make more than a theoretical physics post-doc and deal with a lot less stress, but most people would agree that getting a Ph.D in theoretical physics requires more skill than becoming a plumber.