Why would they require these hours? In the U.S. I think they would need to pay time and a half for anything north of 40-hours. Seems like it would be cheaper to hire more workers and not force the overtime. Then they might be able to increase the salary some. Everyone wins except the people who are willing to sacrifice the time for time and a half pay.
This is only accurate inasmuch as most salaried employees are overtime exempt for other reasons (e.g. because they are executive or administrative professionals). Paying employees a salary, on its own, does not make them overtime exempt.
Is there ever a situation where it makes sense to pay fixed salaries to non-exempt employees?
Sometimes overtime bonuses get used as an incentive for salaried employees to work more but I guess it's more a bonus than overtime pay.
AIUI almost all salaried employees are exempt from overtime pay in the US.