I think the purpose of schooling is to prepare kids for making good decisions about their adult lives, including what their work will be and what they should spend their time and attention on.
Childhood is 18 years. Adulthood is 60 more, at least. Preparing for adulthood is really really difficult, even if your parents would do anything for you, including homeschooling you. Because they can't do everything. Adult life is difficult and lonely, moreso without lots of preparation.