My neighbor teaches in a Philly high school. If you heard some of the horror stories he's shared, you'd be amazed that ANY urban blacks graduate high school.
The fault (of course) is largely the parents. Most just don't care what happens to their kids - when kids get shot (happens every day) they just kind of shrug their shoulders. If they are among those who do care, they can't afford to do anything about it.
The gov't schools aren't organized for the good of the students - they're "organized" for the good of the unions.