I'm from a poor area where there was a super-selective grammar school system.All of my parents' siblings passed the 11+. A grammar school education was the only way to improve your life in those days.
I passed too, but the school turned comprehensive while I was there. I did ok, went to university etc. However I do not believe my rather strict, rigorous education based on a narrow definition of "ability" is a patch on my dd' s state school education. She may simply have been lucky, but I feel the teaching is better, pupils are better-rounded and there are more opportunities for achievement both at school and extracurricularly (if that's a word)!.
I think the days of the Grammar School are over, and rightly so. Neither do I believe that state schools, in the main, are the awful places that they are made out to be.