I know a lot of teachers, and not a single one has ever mentioned these things as values or design goals. I've never seen anything like this in any discussion of curriculum or pedagogy.
It's not plausible that they're all managing to keep it a secret. Someone would have spilled the beans, for example some early 20th century teacher writing a memoir, or something like that.
So, a fair guess is that if it's true, it's an example of a system that has evolved away from its original goals.
Um, obviously this would have been the design more than a century ago when the current school system was put into place. These days we seem to mainly do what we do because that is "how it has always been done". Tradition! You see little efforts to change things up (for example, special classes for advanced students), but for the most part you are still expected to show up at 7am, eat lunch at a specific time, go to the bathroom during breaks, leave at 3pm, sit in a desk for an hour plus at a time, etc.
I don't think there is some grand conspiracy. I think educators are not willing to go totally against the grain and absolutely throw out everything we do right now and start from scratch. For instance, school time before 9am is insane. Kids need more sleep than that. How about kids can get up and leave the classroom and go to the bathroom or go and eat whenever they want? Do we really need classrooms? Do we need dedicated buildings for school? Do we need schedules? Do all kids really need math, science, history, etc.? Just because we have always done things one way doesn't mean we have to keep doing them that way.
It's not plausible that they're all managing to keep it a secret. Someone would have spilled the beans, for example some early 20th century teacher writing a memoir, or something like that.
So, a fair guess is that if it's true, it's an example of a system that has evolved away from its original goals.