I don't think the question is can people do it so much as should they be forced to do it. I could work 6 days a week with 1 day off at minimum wage if I was forced to, but is that a good thing? Hell, I could work 7 days a week as long as I got enough sleep to recover each day, but again, is that a good thing?
60 hour weeks basically means 5 days a week you're only working and sleeping. Kind of a
ty life, especially if you want to have hobbies or a family that you actually see. Doing that for 20 years and you're basically banking on doing all your living and enjoying life once you retire. Hopefully you live long enough to make use of it... I've heard the average life expectancy for UPS retirees is like 5 years which doesn't sound like a very good deal to me.
Don't get me wrong, if you want those kind of hours, that's another matter entirely. More power to you if you have a goal or plan in mind with that kind of OT.