Yeah but you can’t really quantify “happiness based increased productivity” on a spreadsheet as easily as “pay rise” or “stopping union expenses” so, ya know…
You can, though.
Not as easily, but it has been quantified.
https://scholar.harvard.edu/files/nataliaemanuel/files/emanuel_jmp.pdf
https://www.waldenu.edu/programs/business/resource/shortened-work-weeks-what-studies-show
We know these things for pretty much certain. The only people who pretend “the science isn’t in” are the people who stand to gain when employees are exploited. So, ya know…