where they're lucky to survive even getting to school.

I think that's the biggest thing. When you have a culture of fear and kids worried about getting beat or worse and no one pays attention it is impossible to learn in that environment even for the kids who want to learn. That was me in the first school I went to when I moved to the US. I basically just kept my head down and tried to not be killed or get my ass kicked.

Then my parents saved some money and moved to a district that wasn't rich but most kids had two parent households and most kids were pushed to do well in school. It also happened to be majority Asian which I am as well. I thrived in that school as did most kids. Most of the kids from that school now have good jobs and good lives.

You can't teach kids when the parents don't give a shit. There's a critical mass, if you have one bad kid and a bunch of decent kids the majority culture will still be in control. Once you have enough kids who don't give a shit it flips and the school turns to crap.