I am in a "diverse" school district but kids are in a good school. It has probably about 10 elementary, 2 middle, and 2 high schools. As you know the boundary are drawn for each school in the US so you go to the one your house is in.
So, we have the same funding, same staff rotating around them, same management, but different parents and therefore different income level and cultural background.
You probably knows what the result look like and I will not need to say anything that will involve politics. Yes there's overlap and there are people who care in the low income under-achieving group who raised their children correctly, yet the statistics is that in our society (at least in US), parenting is a huge problem, and resources parents spend for their children vary wildly (parenting time, whether there's a housewife at home, tutoring and enrichment courses, coaching on college admission letters, whether parents teach the kids about finance and investment early, whether the parents have disciplines themselves, whether the parents divorce, whether the parents are abusive, whether the parents have addiction problem, etc).
We cannot throw money at school to get result without fixing the parents, unless you want to pay teachers to parent the kids, then you get into all sorts of political problems.