Perhaps you're labouring under the illusion that education is for your good as opposed to the good of those who manage people? Why change a winning formula?
The practical purpose of public schooling is to A) catch the odd prodigy to send to the big leagues with the private school kids, B) get the well-behaved used to 9-5 hours, and C) have somewhere to keep the rest while the parents work.
University used to be just the first group, nowadays it includes the second.
I guess your comment is provocative intentionally. There are many countries in the world where - thankfully- certain public schools/universities are more prestigious than private ones (it comes to mind Germany, Switzerland, Spain, France).
About B) and C) I sort of agree though
