[ZenGum]

The family environment is of course enormously important - probably more important that the school. But that doesn't justify calling "end of story". School is still part of the story.
It's very hard to see how we can "change the family" without getting outrageously invasive. Short of forced fostering or institutionalization, there is only so much we can do. These extreme options were tried in Australia and are now regretted.
But we can work on school systems relatively easily. Getting the parents more involved in their kids' learning might help, but won't address the worst cases. We should do what we can, but not expect huge rapid progress.