Who's investigating the reasons behind all the burnout and erosion everywhere ?
Remedies? Either cultural (it just becomes unthinkable to work beyond X, because that's taboo) or legal (limits on how much you're allowed to work).
Being productive doesn't give you more free time. It just means that you get more work.
"Businesses" don't really do much of anything. What you really mean is the billionaire executives at the top of them.
See page 44 of the paper below.
You can look at Income, Wealth (net worth) or financial resources. Net Worth is probably the best estimate. You'll notice the top 1% has ~40% of the wealth. The next 4% have ~30% of the wealth.
So it would be very inaccurate to suggest that the "majority" of wealth and upside is accrued to the middle class, at least in the US.
"Household Wealth Trends in the United States, 1962 to 2016: Has Middle Class Wealth Recovered?" Edward N. Wolff
NBER Working Paper No. 24085 Issued in November 2017 https://www.nber.org/papers/w24085
I'm convinced that a lot of people would be ready to work 'harder' when the work is well organized and done.