A 60 hour work week is 10 hours a day 6 days out of 7. Let's add two hours for commuting both ways and getting ready to go to work. Subtract that plus 8 hours for sleeping. Leaves 4 hours in a day for everything else. Let's say an hour to prepare meals and feed yourself. Down to 3 hours. Random crap like food shopping is going to take some hours from that.
So a max of what? 3 hours out of 24 that are not spent just keeping yourself alive.
What a glorious existence we could have, if we followed your advice and did a min wage job for 60 bleeding hours a week. Glorious.