It, presuming you refer to summer vacation, is the default state of affairs. It does not need to serve a purpose, as human beings have natural rights to liberty. It does not need to serve a purpose any more than days off from one's job if one has sufficient resources to survive without working. The implicit assumption of your statement here is kind of monstrous - that human beings are the property of the state who must justify their time away from the state's control. Much worse, when you consider we are discussing children, here.

No, your language is empty and devoid of genuine substance, phrased in such a way as to negate the idea of alternatives to the implicit assumptions. That makes it rhetoric. Whether for a worthy cause or correct mindset makes no difference.
Applied to the criminal justice system, this line of thinking is "guilty until proven innocent." There is no need for empirical data to prove a negative, and there is no moral reason why people have to justify their lack of production or activity or leisure to do as they please.
That has never been my experience, as a student or a teacher. And even if it were true, you have not made any sort of case for why people should be compelled to retain their "training" (as if they are animals - this is the place you start going when you think of human beings as assets of the state, whose free action must be justified in the interests of the state). Another point you are not addressing is whether or not avoiding the need for "retraining" is sufficient grounds to justify year-round schooling. Considering how much useless activity goes on in schools, the value of being retrained all on its own is a highly dubious proposition.

Almost any activity or action requires greater effort to begin. That does not mean there is no reason to stop. By your logic, airplanes should never land, given the disproportionate energy and fuel needed to get them back into the air.

Furthermore, if that anecdotal theory about needing to overcome the inertia of the break WERE correct, it could just as easily suggest that schooling itself is an unnaturally stressful environment and activity. Why do you have to pound individuals into a special mode of behavior for an archaic educational model? It certainly has nothing to do with anything worthy later in life. Self-discipline and independent thought are far more useful virtues to develop, than accustoming oneself to the routine of a second-rate educational method.

How many dual incomes would be necessary without the expenses of schools, including taxes and the higher costs of clothing and feeding the students during the school day? And in any event, dual income homes have other ways of child supervision when school is not in session (normal people tending to work longer days than school teachers). The expansion of such methods might be far more cost effective than the extreme expenses to the community of increasing the overhead, salaries and administrative costs of running schools for longer periods of time.

The reality of teachers being glorified babysitters is generally considered an argument AGAINST the educational establishment, anyway.

Who the fuck's business is it what children do with their time? That such an idea could be entertained or voiced in public policy is a symptom of serious distortion of priorities and perspectives vis a vis the relationship between government and citizens.

The better question should be, what is there to gain from sending kids off to an overpriced, glorified day-care system at enormous expense to the public?

And air conditioning is free and magic in a world where the government is compelling people to use more efficient light bulbs, in the same of energy scarcity?
No, eight to nine months to be taught excessively simple, and increasingly low-level basic skills is excessive and outdated, unless the goal is some sort of indoctrination.
. They have nothing to do with school quality, and are in fact, the saving grace for many of those students.

Which is exactly my point. Kids from families like that are already fucked, and forcing them to spend more time in school will not alter their situations. Much less forcing students from good families to spend more time away from their positive influence, so the minority from bad families can get practice for their inevitable prison time.

Your point being? All you have done with these last two statements is acknowledge the primacy of the family to the educational process, while attempting to make the point that the student should spend less time with the family and more time in a bureaucratic, regimented institution.
Too bad we have a 13th Amendment and are not a totalitarian dictatorship to make something like that a thing. Are you even looking at what you are writing here?

You CANNOT be this ignorant, can you? Look, just read up on the effects of Abbot vs Burke in the NJ Supreme Court, and shut up until you know what you are talking about.

For the informative purposes of this discussion, as a result of that decision, the worst schools in NJ are the ones that have been receiving the most money from the state. The very best schools, of course, receive no money from the state, but that's a whole separate issue.

What summers thing? The status quo, or your proposal to increase the amount of time children spend at the mercy of a system you characterize as mismanaged resources?

Parenting is far and away a more important influence on children's lives and development, and sorry to say to such a state-obsessed person (as I must consider someone who speaks of ordering human lives to serve the interests of the state as you do in this post), but there is no bureaucratic, administrative or legislative fix for problems in those areas, and the most perfect and caring school system in the world will do little good against the bad influence of a parent, even if you force the kid to attend 45 weeks out of the year. Anyway, that hypothetical super school is just a dream, and equally unlikely to be fixed by any sort of public policy. We have no way to reliably create such an institution, and the amount of good it could do is highly suspect, and certainly negligible on a cost-efficiency basis considering what the expense would be.

Your idiotic speculation about the possibility of diverting resources to poorer schools, is per Abbott and numerous similar decisions around the country, only the policy and status quo of the last 30 years or so, to little or no improvement, and often regression. Public schools are a joke compared to the effectiveness of private education, especially considering the absurdly greater amount of money spent per student in a public school district, compared to a private school, whose students and read, write and figure in circles around the public schools'.

Increasing the school year will drastically increase the amount of money needed for the public school system, put undue burdens on the institution that is actually helping the children with any realistic future (the family), and do nothing more than expose the children to an institution characterized by mismanagement, waste, regimentation and litigious mentalities, where they encounter petty crime, peer violence and premature exposure to illicit activity and substance abuse, while learning to value social interaction and peer approval over individual thought and self-determination. They will learn at a rate paced to the least-capable students, and assigned to educational environments on the basis of factors such as age or demographics, rather than ability.

But people like you go around demanding by what rationale do people go about their lives as they please instead of turning those lives over to these moribund institutions of what are optimistically and euphemistically called "learning."