Dog Days of Summer

Yes, our school calendar has three months "off" for summer vacation.
I never really understood why we have that time off. We're not working the fields anymore.
I've always done academics in the summer. Something to keep learning. Yet we condition our teens that they can stop learning after the first part of June and not read/write/calculate until the end of August.
Many teachers need their break- I respect that (actually, many work another job). If the students are not academically at grade level, then they should be required to continue learning through summer...