How well off.
Ok. And I think someone objectively trying to find out such things would ask these questions. My comments, specifically.
"how has output per worker changed?"
That shouldn't have much to do with how well-off workers are. A higher number doesn't mean they are working harder. Indeed, I might add some things here that you didn't: injuries in the workplace, what is acceptable as 'sick', eg. depression and mental health and so on. Also what constitutes harassment and fair treatment. (I assume you're looking at workplace conditions with that stat, output per worker)
" Changes in hours per week worked, especially for those on salary? How have work benefits changed? Pensions? How has job security changed?"
Those are all related, and likely have gone worse for workers, although I think the last two are the most impactful.
I have no idea. 30's and 40's were very stressful times. I'm talking post-WWII.
Some things about them were a lot better than in the past, though. But ok - we're acknowledging that 'progress' is a thing. That's not a small deal. Some will tell you that the masses have no right to expect improvement in their lot over time.