It is the school systems fault because they should be making sure the students are paying attention and actually learning. If the kid is screwing around in class, being a hooligan, the school system should punish them and force them to pay attention. We cant blame the government for all issues. If your funding is so low, cut football or cheer. Ya pump a ton of money into that.
From a Canadian perspective - struggling inner-city schools need the most funding and the best teachers. Where I live, if a school and students are struggling, added resources are poured into the problem. Under the U.S. Model, if a school under-performs, resources are taken away as a punishment. The results are clear. Canadian students consistently rank MUCH higher in all international education tests, graduate at far higher levels; illiteracy is far less common. Tragically, in the U.S. 20% of high school seniors are functionally illiterate and that rate has not changed in over a decade. I feel sadness for those children.
The school system is not to blame over this issue for two reasons. First, some schools recieve lack of funds to operate. Lack of funds means that schools will not be able to buy the proper tools needed to teach each individual student correctly. Also the second reason why it isn't their fault is because some kids simply choose not to learn. No matter the funds if a student wishes not to learn they will simply choose not to do school work and as a result they will preform poorly on tests created to see how well the student is doing. The blame only lies within the individual for not wishing to learn and the lack of funds recieved.
Several recent studies showed that a student's performance in school is only about 25% determined by what actually happens in school. The remaining 75% is determined by factors completely out of the school system's control- parental involvement, poverty, hunger, and other social issues.
Public schools are simply a convenient scapegoat for people who don't want to face up to the fact that they are responsible for the failures of their children, or people who want to deny that our poverty rate (quite a huge one for a developed country) makes it near impossible for many people to advance from the station to which they were born.