> What about parents? That would seem like a natural market for a product that could replace expensive private school tuition (or paying high property taxes in order to be in a good public school district)

Quality of education is one factor among many when making the choice to send your child to a private school or move to a prosperous community with well funded public schools.

Another major one is social clustering, premised on the expectations that children will pick up beneficial cultural traits from similarly higher privilege peers that will help them advance.

Edu software can't provide the social benefits of exclusive schools (whether they are private or public). Parents know that which is why if they can afford to, they avoid underperforming schools.