That's very true. Widespread, high quality public education is a must.
Some school districts are now having a measure of success with having ONE school but tracking the kids into "accelerated" or "regular" programs and elevating the resources for both.
There was a whole podcast about it: https://www.nytimes.com/2020/07/23/podcasts/nice-white-paren...
This happened as a result of a large-enough number of well-to-do parents no longer being able to get their kids into very desirable and academically rigorous city-wide schools, so they effectively "took over" a neighborhood public/charter school by participating VERY HEAVILY in the PTA, the school's funding, and getting deeply involved with the ALL the kids, teachers and administration.
From what I can tell, it required a very uncomfortable and ongoing dialog about race and class. Not every school in every big city can do this, IMHO, but AFAICT it lead to better outcomes for all the students, including the at-risk students.
Given that, it's less surprising to me that the bottom tier public schools in these areas wind up so much shittier than the average public school.
I'm thinking either it is externally visible or the factor is "solvable" for every student, meaning a school with bad students will receive more policies/measures to boost their performance as everyone is suffering from the same underlying problems. Of course this assumes that poorly performing schools get support at all.
but at the school level what can they do?
Lots, actually, but it's very resource constrained, so once again, the relationship between money-poor schools and bad students plays out.
There are a variety of diversion programs that have been tried and shown great success with problem kids, but that requires staffing so that disruptors get more teacher attention than they otherwise would in a class of 35. Having competent, active counselling services in schools does a lot, too.
With that said, it's not my wife's experience (as an inner city high school teacher) that disruptors are the problem. They're a problem, but there are lots of ways to handle them, individually or in groups.
The way kids get shafted in poor schools is high teacher:student ratios that reduce or eliminate any individual attention a kid might receive, coupled with poor facilities and supplies. You rightly identify parental involvement as a key factor in school success, but the flip side is that kids lacking parental involvement are denied any individual attention in schools that are simply overcrowded and understaffed. And the kind of attention I'm talking about isn't substitute parenting, it's just following up with kids on assignments and attendance.
https://www.usnews.com/education/best-high-schools/illinois/...
99.9% minority students, 94% economically disadvantaged. Testing scores are horrible...across the board. 2.8% percentile for their SAT scores...26% of the students took an AP exam and 3% those that took them scored acceptable (3). This brings up a lot of questions...like why is a school that can barely graduate kids (54%) focused on having 1 out of every 4 seniors take an AP exam?