Since I got as much done as when I worked 60+ hours, no one seemed to care.
All these comments are valid. I suspect that people would get as much done in a solid 30 hours of working than the do in 80 hours of burnout. There was time (70's 80's) where, because of striking coal miners causing power shortages, UK industries were forced to a 3-day work week. IIRC productivity in those 3 days was about 90% of the 5-day week. Whether that would have been sustainable we'll never know because once the strike was settled the week went back to 5 days.
It is difficult to soar with the eagles when you work with turkeys.