I am a selective-school educated professional, with intelligent, high performing (academically) children, and I recognise NOTHING from your premise, OP.
I want my DC to do well academically. They want to do well academically, and they work at it.
They are at a comprehensive school, in top sets. This is a school in a pretty non-leafy area of S London. There are gangs on local estates, between our house and the school, for example. And the kids of those families are in the school. There is a high ratio of young people within the school who are on FSM. At no time has anyone ever had anything to say about children within the school who are high achievers. There is no bullying due to being a 'swot' or 'geek', these words are not used. The school has an orchestra way better than anything at my old school. The school supports (and rewards , and flaunts) its high achieving students. And makes opportunities for them. It also supports students with challenges, lower learning speeds, specific SENs, etc etc and pushes them to their best potential. That is what a comprehensive school is.
I want academic excellence for my kids, they want it for themselves, it is well catered or within their good comprehensive school.
Though I do think the 5 A*-C performance measure pressurises schools to support he middle to achieve this as a priority. BUT Grammars often coast: results reflect the ability of the selective intake, VA scores are no more than they should be.
VolunteerAsATribe: there is a proper study which demonstrates that Kent (as a fully selective county) does not achieve overall better results than comparable areas, but I can't remember who by. Here is a FT exploration of some data which suggests the same thing here