This is for "First-Line Supervisors of Construction Trades and Extraction Workers." Does this represent the "average tradesperson" at age 40?
If we dig into the BLS numbers for the people doing the work in what HN tends to talk about as trade workers:
Plumber - median $61,550 per year [1]
HVAC tech - median $57,300 per year [2]
Electrician - median $61,590 per year [3]
Framer(Carpenter) - median $56,350 per year [4]
Bricklayer(Mason) - median $53,010 per year[5]
Software engineer - median $130,160 per year [6]
Of course, these are national numbers. We could pick and choose geographical areas to bump up the averages.
It isn't immediately obvious to me what data source could give us a good answer to net worth by age for any of these careers. That is why I asked if you had a reference for it. It's even murkier when looking for data on when someone in the trades buys a house on average.
My intuition (and I definitely don't mind being proved wrong) is that high earning, high-ish net worth trade workers is a story we want very much want to be true. But I just don't think it is, especially if we are talking about the average case.
[1] https://www.bls.gov/ooh/construction-and-extraction/plumbers-pipefitters-and-steamfitters.htm
[2] https://www.bls.gov/ooh/installation-maintenance-and-repair/heating-air-conditioning-and-refrigeration-mechanics-and-installers.htm
[3] https://www.bls.gov/ooh/construction-and-extraction/electricians.htm
[4] https://www.bls.gov/ooh/construction-and-extraction/carpenters.htm
[5] https://www.bls.gov/ooh/construction-and-extraction/brickmasons-blockmasons-and-stonemasons.htm
[6] https://www.bls.gov/ooh/computer-and-information-technology/software-developers.htm