As another poster said, it probably has to do with having enough classroom time to remain accredited. Accreditation is very important in this day and age. I personally would never send children to a school that was not accredited.
We have a traditional Catholic school in our city. It is not affiliated with a parish, but the children in the school (kindergarten through 12 th grade) attend the Traditional Latin Mass once a week. So even these children from very traditional-leaning Catholic families don’t attend Mass every day. I’m pretty certain this is so that the school can offer enough classroom hours to remain accredited, which is a major factor in why parents will choose a school.
Yes, of course a Catholic school can start their day earlier and/or run the day later. But this would mean longer hours for the teachers and other staff, which means a raise in salaries, which means an increase in tuition, which means that a number of families will not be able to afford the school, which means another increase in tuition for those students who remain in the school to make up for the loss of students…
Another thing to consider is that if the school day goes too long, the children have a more difficult time getting involved in various community activities, which are often scheduled to coincide with the area school schedules. E.g., our skating rink has a few after-school freestyles (practice sessions) for figure skaters. Many older children need to use both of these freestyles, the first of which begins at around 3:30 p.m. Most of the schools in our city end their day by 3:00 p.m. (The school that my children attended still ends the day at 3:15 p.m., which makes it a fast drive to the rink, but it’s still possible). If a school day goes much later than 3:00 p.m., parents can’t get their children to the freestyle. This could be reason enough for parents to switch schools.
The skating example is just one example. There are plenty of others, and not all have to do with sports. There are also various arts activities (music and dance), and other activities like scouting, community centers, etc. Children and their parents want to be involved with these activities, and schools have to be mindful of this when planning the schedule.
One thing to consider is that many schools offer after-school care for children with parents who work at jobs outside their home. The employees at this after-school care would lose some of their work hours if the school day were increased, and this might be a situation that would force them to resign and find another job where their hours would provide them with sufficient income.
You see, there are plenty of reasons why a daily Mass is difficult for schools.
At our parish, there are three daily Masses. One begins at 6:30 a.m., which means that parents who wish their children to attend daily Mass can bring them to this Mass, which ends by 7:00 a.m. The parish school doesn’t start until 8:00 a.m., so the parent would have to find something to do with their children until the school day begins, but IMO, that wouldn’t be such a bad deal! It would be ideal study time. The second daily Mass starts at 8:30 a.m., and this is the Mass that the school attends once a week. There is also a third daily Mass at 5:30 p.m., and this would be another option for parents who wish for their children to attend Daily Mass.
I’m wondering if perhaps the OP can find a parish in their city that has a daily Mass at a time that their family can attend that doesn’t conflict with the parish school schedule.