9-5 Desk Pilot here, as well as all the valid reasons above think about this one; if my office wants people to work longer hours but the company across the road is advertising shorter hours, you can guess which job people will choose.
Call centres have exceptionally high attrition and where I live, there are loads. They have to be competitive to retain the best staff. Without belittling the role, you don’t need experience, qualifications or a minimum fitness level to do a lot of those jobs. You don’t need to have been an apprentice or have been to Uni. As you can imagine, anyone can apply for these jobs. That’s what makes it such a competitive sector.
Also you schedule to meet your predicted call volumes. These aren’t a machine that runs constantly 24 hours a day, there are peak times and lulls. If you have people sat on their hands doing nothing, you’re losing money. It’s easier to cover this with shorter shifts. Have the people in when you need them. Also look at what your product it. If it’s customer service, it’s difficult to deliver the best you can after you’ve been doing it for 10 hours. From a management view, it doesn’t make sense for people to work longer hours.
Rant over.