If not for the lack of maintenance culture and the lack of proper investment into the public sector, would it have degenerated to the point where schooling in a public school that's built by tax payers money becomes a disadvantage?

People's financial status differs and with how expensive private schools are, not all parents can afford to spend such amount of money for Thier kids to get such education when they can pay a lesser amount for a public school that offers same service and use what's almost like the same curriculum. Would you rather have a parent spend all his earning on a child's school fees and find it deficult to take care of the families needs when public schools that are cheap can be a good options combined with other things like paying for the child's private lesson fee and purchasing of good text book for the kids?

Most private schools are just sophisticated centres that lacks a lot of real learning aids compared to what an intentional parent can bring out of a child that's attending a public school and still has access to good text books and private lesson teacher that will also be of great help to the child.