The way we make public schools yield better results involves changing our culture...
In other words, we are screwed...
You're closing in on the problem, but missing the mark.
If I may be so bold, but it seems to me that everyone in this thread is beating around the bush and completely missing the real problem. The problem is purely Cultural and has little to do, although is influenced by that Culture, the System setup to educate. The real issue here is Decadence, over stimulation, and everybody trying to scratch their way to the Top in a Society where getting to the Top is becoming increasingly(even despite the recent Economic troubles)difficult. This is why Materialism and Massive Debt is rampant from the very bottom to the very top of Society, everyone is living the Dream even if that Dream is beyond their means.
I wish I could give an easy solution, but I can't. the problem has been going on for so long that the very Infrastructure where people live assumes that the vast majority will have the means of a Lifestyle that no longer is feasible. This has resulted in growing inefficiencies for the average citizen which constantly pushes that citizen further and further away from the assumed necessary Lifestyle to maintain the system.
One of these Infrastructure induced inefficiencies, going off on a tangent, is the Automobile/Suburb relationship. In a highly Urbanized society, such as we are in North America, there is really little need for an Automobile for Transportation. Yet we have chosen to saddle ourselves with that, because it's part of the Dream, "Freedom", and our Materialism. The amount of Money we spend on the Automobile, both Personally and Publicly is a drag on us all though. Constantly putting stresses on the Individual to Work harder and longer which makes Parenting increasingly difficult in itself, never mind the idea of them being Good or Bad Parents.
There are no easy solutions, for the problem is deeply entrenched and entirely of our own creation in poorly conceived Values. Until those Values change however, it is very unlikely the Public Education system can be improved.