Public schools have specifically failed at allowing every child to advance at their own level with no restrictions. It caters to the kids in the middle, with enormous amounts of resources thrown at kids on the bottom. The struggle to work with groups of kids with such varying needs is a specific complaint of teachers.

We pretend that public schools have standards they are required to meet, but with 1/5 of Americans being functionally illiterate, I think we need to accept that no real standards exist or are adhered to.