Well, really the purpose is to inculcate the next generation with the common culture, history, rules and norms, as well as the practical knowledge they will need to become self-supporting functioning adults in society.

Every human civilization and tribal community does this.

It's why we in the USA spend so much time in the early grades not just on arithmetic and ABCs, but on stuff like the Pilgrims, the first Thanksgiving, George Washington, Benjamin Franklin, etc. It's not really anything anyone needs to know for day to day life in 2025, but it's a set of common stories that we all can relate to, draw analogies to, and yes rally around if called to do so. I'm not sure really how much this is true today, I'm reflecting on my experience in the 1970s.

Public schools are also a de facto childcare, welfare, and healthcare delivery system. Education is only one facet of the modern public school system in today's society.

Why should kids like Brian's be forced together with those that need to be kept out of trouble?

But it doesn’t have to be the only purpose.