It's an extremely good question. I do look at it that way. When we were a country that had a more rural economy, children were educated at home and learned to read almost before they could go to school. The economic reality of the time was that they needed children to go to school from September until June so they could work on the harvest. That's why we have summers off in the school system.
The economic reality now is that parents are returning to the workforce and there needs to be some kind of system to educate children beyond September to June, in the summer months we normally have off now, and extend that to a lower age because of the economic necessities. Our school system was set up with one economic necessity; we have a new one now. That may be the difference.