If the latter are paying you "what you're worth" in return for 50-60 hours a week, aren't you getting paid 50-75% of what you're worth...? I think you've been fooled.
...no? Salaried jobs break the direct correlation between hours worked and hours paid, but it doesn't mean there's no plan there. There are absolutely salaried jobs which openly expect 50+ hours, it's up to you to decide if the salary matches the expectation.
(There are plenty of jobs which aren't upfront about it, obviously. That's more of a scam.)