Yes the demographics of these schools somewhat reflect the demographics of the nieborhood my child was also accepted at Stuy, but it would have been about a 2 hour commute each way every day on top of the extra work. Most people in their right mind would forego that challenge if they have other options.
One other thing I might mention, is that they used to make the rankings public, back when my kid was in 8th grade. I don’t know whether they still do. They would actually read off the rankings in the middle school classroom. A lot of parents objected to this, so they have probably stopped doing it. If they haven’t, it’s a thought that maybe they should. It wouldn’t change things much but it would keep tempers down.