"Since the beginning of time a quality education's generally also been the preserve of the wealthy..."
Not when I was at school it wasn't, Jim, as I explained earlier. And my school probably provided just about the highest quality education that could be obtained without paying (and in many respects better than some fee-paying schools of the time provided).
The grammar school conundrum is always attacked with the "not everybody can have it, so nobody can" argument. It then somewhat illogically descends into attacking grammar schools for being so good by comparing them to other schools which are so bad.
No, not everybody can have a grammar school education. Agreed, some of the alternatives are a bit dire. But because they are is no reason whatsoever to scrap grammar schools.