So this is a topic I have all kinds of interest and experience with.
I live in one of those top 100 zipcodes of USA with very small school district. It's plenty diverse racially but completely homogenous financially (i.e. pretty much everyone is rich). I have two kids just a year apart. One just barely didn't make it into gifted & talented program at grade 3, and another one definitely did, and has been in one since then. [Edit] oh and I was in gifted/advanced class myself from grade 7 on, but not here, but in Russia.
Plenty of parents pushed very hard for the kids to test into the gifted program, getting kids tutors and repeatedly testing in. There was one kid I remember who was bright as all get out but a complete asshole in social circumstances that apparently tested 3 times by his parents until he made it (2 highly focused doctors). My kid that tested in actually didn't start in it, but then about a month into 3rd grade complained that he was bored and we were able to move him in.
We've been involved with the teachers on both regular and gifted track. We - and every parent with child in gifted class - are not happy about our school sunsetting it for the district. No teachers - certainly no teachers of advanced classes - were consulted on this effort. None of them are getting any additional help in now trying to teach to all levels, and result will be (already is) a dilution of quality all around.
As with many schools everywhere, and with covid helping, there are some kids departing towards private education where your money talks and you do whatever. Where I live is increasingly unaffordable, too, so we have reduced enrollment because there are just less kids. I do fine but am not at economic place to afford private education, my offer to kids is where I live, which even with the dilution is still excellent education.
We (and almost every parent around us) are very engaged with schools with volunteering and additional funding. In fact I am a treasurer of the schools foundation that donates up to a $1 million/year to school for all kinds of things, mostly general funding. That tends to help but really, even our little district needs like extra ~$20mil to fund what we're supposed to.
Anyhow, on cleverness nd equity, what it boils down to me is that the world is becoming just one big lake now with talent being increasingly able to accrue huge benefits. This talent needs education and people who want best for their kids (including me) will do whatever is necessary to get that. This is why there is extra tutoring in china and private schools in USA and fancy boarding schools in UK for $$$. If public schools do remove this equity stuff, it'll just float via money to those other areas. It isn't bad/good, it just is.
Anyhow, a bit of a rant/laundry list, but here you have it.