That paper that you're citing is from 2022; hardly what I'd call historic. And is 2 in real dollars? Because it doesn't look like it and I wonder if it would be just a flat line if it was.

I'll say that I've worked along side my cousin's baby-daddy (I think in future I'll just call him "T" as that's less unwieldy), and he's a fine painter, but ultimately there just isn't that much to the job. I remember the first time I used a paint sprayer on a new construction job myself; basically you just need to learn where the trigger is and in a minute you can paint a wall that would take an hour with a roller.