It's true, in previous eras children were put straight to work as soon as they were useful. This has been true in every agrarian society across all cultures. Society increased in complexity to the point that it's quite hard to become an independent adult if you go straight to work as a young child, hence the need for an education. However the goal has always been the same: condition yourself (skills, mindset, habits, behaviour, etc.) as required to become a functional, independent contributor to society.
What is new and unusual is the idea that children should have a "childhood" of recreation, protected from the realities of work and life.
Attending an educational institution as a child is much preferable to working on a farm, or in a mine, don't you think?
There is proof of this everywhere. The vast majority of humans throughout history never engaged in such a system, and plenty of contemporary humans don't either.
What is your ideology?