I was wondering that. :).
It really in my mind ends with the unionization of teachers & the more widespread public education system - which, at least in New York City, was a way to deal with "the immigrant hordes.". So that's around 1890, isn't it?
The one room schoolroom of course still exists ....
You changed the name quite literally as I was adding Grandpa Rev. Ralph Wheelock, America's First Public School Teacher and I got so confused about where the project went and when I had joined this other one. :)
I like inclusivity, especially at the start of projects.