Summer vacations as they exist in the US are counter productive, pointless and a hold over from pre-industrial schooling when rich families would pull their kids out of school during the hot summers to go somewhere cooler leaving the school with less funding and without their stat pupils so the trend rapidly developed of just going to extended recess till the weather cooled and rich kids returned.
The argument that it was for farmers is patently false. Farmers plant in the spring and harvest in the fall, both times schools are in session. And livestock farmers have year round commitments so the idea of pulling students only for the summer is equally silly. It all comes down to rich kids.
A sensible school calendar would be year round, with those 6-8 weeks of summer break broken up and spliced elsewhere into the calendar, reducing the amount of material students would forget, basically the entire first quarter coming back for most schools is just going over everything learned the previous spring to catch up. It's not one for one but by the time kids get through 8th grade almost 2 years of their schooling has been spent relearning something they already learned.
We could do so much better for kids if we abandoned the ridiculous calender most schools use and alter the actual hours kids are in school to better reflect on what they learned and absorb it rather than just memorizing enough for the next test and moving on.
Counterpoint, wouldn't it be better to have 3 weeks for Christmas, 2 weeks for spring break/easter, 2 weeks in the summer and then an extra week or two break in the fall? Depending how you organize it kids could have up to 2 weeks off after every quarter/major exams.
Or, going the other direction, you could condense it down to every other or even every Friday off, meaning 3 days weekends and 4 day work weeks for youth.
I get the sentiment, that having 2 months or more off as a kid was great and I certainly enjoyed it at the time, but looking back it was such a bad system and I certainly would have adapted better to school if I had more breaks from it throughout the year rather than one long absence in the summer. It's not that summer vacation needs go away entirely, it just needs to be revamped to a more manageable break and that excess time off spread out throughout the year, particularly around times where students experience the most stress so they can decompress.