In a society where everyone receives equal education regardless of who they are, why would they all have to go to a boarding school, rather than a public school?
This is at no extra cost to the parents. They are kept in dorms separated by age, and are required to attend from ages 5-16. They are not allowed to just opt out of schooling.
In the case that it helps, the people doing this are dwarves. They are your typical Tolkien ones at this point in development. The children are taught subjects like math, language, history, science, life skills, and physical education along with whichever options they choose. This is also a very fair, equal society.
EDIT: I am judging by plausibility and cost effectiveness.