This is a sore subject with me.
As a former educator, both at the secondary and college level, and with a wife that is currently a middle school teacher, I can tell you that students could be well educated with a tiny fraction of the amount of money spent on education. You just would not believe where all the money goes!
DC spends about $18,000 per student per year. Their average student to teacher ratio is 13, that's $234,ooo per teacher, but the average teacher salary is $77,500. So where does the other $156,500 go? If you've got, say 20 teachers in the school, we're talking about $3,130,000 being spent on the students in that school that is NOT going directly towards educating them!
I have maintained that any subject I have taught (with the exception of computer programming), I could teach with just a blackboard and some chalk out on a hillside with the students sitting on the ground. No school building required, no principle, no classroom, no electricity even... And yes, I actually did hold class outside a few times just to prove my point.
In public schools, really all it takes is parental support of the teachers. But you can't put all the blame the lack of parental support on the parents. When the educational system decided that they knew better than parents what was good for the kids, and started openly defying the wishes of the parents, how can you then expect the parents to support the teachers???