I suppose the key statistic is that grammars have expanded 30% in recent years (by pupil numbers - no new ones have been built apart from a couple of annexe situations).
So whatever the academics say, the parental demand is very high.
Probably more worthwhile unpicking why that is - as some posters are doing.
I'm in a grammar area and will be sending DD to a comprehensive, because grammar wouldn't suit her.
I don't think all schools should be the same though. There should be a range of options.
And the average size should definitely be smaller. Around 800-1,000 not 1,500-2,000.