Besides, rich kids go on overseas vacations during the summer.
What you find when you look at the numbers is an awful lot of White collar firms simply get less done during the summer months. "We expect to move forward on that project, but we're blocked on the report from the ads team, and 2/3 of the ads team just took a week-long vacation with their families" is a common pattern in summer.
Schooling at home is a lot of work for someone, and it is work daycares aren't prepared nor staffed for.
I think I stopped having a daycare by the age of 10 or 11... I grew up as a Latch key kid...
I would see my parents at Dinner Time, then Dusk where my 2 curfews. other than that I was outside 90% of the time. of course this was before Internet, Cell Phones, etc... I did not get dial up internet until I was like 16-17 (which by then i was driving so....) , and broadband when I was 18 or 19... Today i talk to parents where they have 24/7 electronic tracking of their children every movements, kids well in to their teens still having babysitters or not being left lone...
Society has grown extremely risk adverse, likely if parents tried Latch key kid at the age I was Child Protective services would be called... In General the reaction to COVID has highlight just how risk adverse society is over all, there are other warning signs, but it has really been a eye opener for me...
I'm a bit skeptical of that explanation in the US because schools close for 3 months every summer, without an accompanying large number of women quitting their jobs.