It’s not like you can fire employees on a whim: the “unrelated reasons” have to be substantial ones, and it’s not clear you can find ones for any employee you want to fire. (Otherwise, you could use such a mechanism to de facto compel your employees to do pretty much anything you want.)
Also, even if you somehow did manage to de facto demand workers to work ten hours a day, if you have to pay hours beyond the eighth as overtime (with a hourly wage substantially higher than the regular one), then it’s cheaper for you to hire ten people eight hours a day each than eight people ten hours a day.
It’s not like you can fire employees on a whim: the “unrelated reasons” have to be substantial ones, and it’s not clear you can find ones for any employee you want to fire. (Otherwise, you could use such a mechanism to de facto compel your employees to do pretty much anything you want.)
Also, even if you somehow did manage to de facto demand workers to work ten hours a day, if you have to pay hours beyond the eighth as overtime (with a hourly wage substantially higher than the regular one), then it’s cheaper for you to hire ten people eight hours a day each than eight people ten hours a day.
Under American law, you basically can fire an employee “on a whim” as long as it isn’t a prohibited reason.
Only if they can’t get another job.
That assumption isn’t that far-fetched. Also, the same applies to doing that to compel them to work extra time (or am I missing something?).