All through my teaching career, forty plus years, there have been schemes proposed to alter the terms of the school year, the four term year being the most sensible, and the one which had the most support.
But it all hinges on the academic university year, and they are totally resistant to any change. Academics use their long holidays for research, writing and publishing, and will not relinquish them easily.
Moving the summer holidays forward to June and July would make good sense,but whenever they are the price of holidays will rise accordingly. Schools will not be sympathetic to children having time off throughout the year for holidays; parents ignore how unsettling it is and how difficult for the child to catch up on work missed.
And parents always say, it hasn't hindered their school careers in any way. Well, they would say that, wouldn't they, the same as they deny family break-ups have any impact on their children.
We see the children in the context of other children, and we know.