You have some rose colored glasses on or just very limited experience with how much of corporate america works.
Practically speaking, few companies actually require 80 hour work weeks. However it's definitely NOT uncommon for a company to classify someone as exempt (even though the law actually sets the bar fairly high for that) and then require OT 'as necessary'...to the tune of 5, 10, maybe 15 hours or more a week. Of course, they'll tell you that the extra $ is factored into your pay (which it might have been once upon a time).
Can you quit? Of course. But is it practical to up and walk away from a job at the drop of a hat? No. Does a company come out and say "hey, work twice as much starting tomorrow"? Of course not. You just get extra work and tighter deadlines, and what started out as a 40-hour week becomes 45, then 50, then you take some work home, then you're doing email on the weekend at your son's bball game or whatever.
Most of the rest of your points only apply if you work at large companies, and even then, only the much more progressive ones. That may be YOUR experience but it's certainly not the norm.