I think you are on to something. At the same time I wonder about content sticking if you don't practice the subject for months. Doing math two months of the year (ignoring the math you might need in physics class) might mean you have to rehash a lot. That said, for many subjects this wouldn't even change anything. How often does learning something in history class currently rely on what you learned a few months ago? Rebec in my biology classes things rarely were connected. For a few weeks we talk about fungi and then for a few weeks about the cardiovascular system.

I slightly disagree. It takes time and repetition for some things to sink in. IMO, moving to more college-like A/B days would be better. I would not expect history lessons to stick if you compressed 180 days of AP Euro into two weeks at eight hours a day. Likewise, math classes moving that fast would give students the feeling they learned a ton without any retention. That said, I feel like literature and writing could be subjects that fit into this model of intensive week-long workshops once each year.

It might not have been the teachers who decided on this schedule.

I hear some tech workers complain that their days are made ineffective by lots of pointless meetings.