Everyone can't be a plumber.
In fact one of the worst "trade offs" of the trades is they can very much be a young mans game.
It gets real hard to sling water heaters up/down tight stairs or pull cable in a 100+ degree attic into your 50s.
Get the young guys to do the lifting, there’s still plenty of room for old guys with experience who know all the tips, tricks and gotchyas.
Edit: Fair point, you don’t want to be entering a trade which requires heavy lifting as an older guy with no experience.
> Everyone can't be a plumber.
Yes, but not for the reasons you say. It’s because if everyone is a plumber, you don’t need plumbers.