Whoever invented the eight hour five day work week is Satan.
Unions. Unions won the five day eight hour workweek after heavy, sometimes bloody conflicts with employers. Before that it was common for workweek to be 10 or 12 hours a day.
Too many people are ignorant of the role Unions played in American history. I assume they were brought up in places where the GOP controls the schools.
The bad news is their power has been systematically eroded for a long time. The good news is they've made a bit of a comeback in the last couple of years. Hopefully this trend continues.