There are a number of bands who keep their crews (or even loan their crews out to other bands when they are not performing/recording/etc.)
People who look at the Rolling Stones and ask “do they really need to tour to make more money?”, they will go on the road with 3 road crews, one building the next date’s stage, one supporting the current stage, and one breaking down the previous date’s stage. This year’s tour may not be that way (something like 21 events).
And when you keep your guitar tech, you know your guitar is safe and that it should be in tune.
And the line I forget to mention there, so these bands ARE the business that some people are employed in for many years even if they aren’t peforming members of the band.
Billy Joel for years, has let his tech people take the stage for a few songs.