UnquietDad
Well, it would be "less unfair" because everyone would at least be using the same system.
Exactly.
And we'd all live in the same areas, and we'd all have the same catchments, and we'd all have exactly the same sort of pupils in the school, and no-one would have any tutoring, and no-one would have school trips that some can't go on...
... oh, so we wouldn't have the "same system" at all.
The squeaky wheel (the middle-class parents, of whom I am a member) tend to be more demanding, more articulate, and more persuasive - and so will get better results.
Of course, some people recognise this, and make strenuous efforts to avail themselves of social mobility... except some wicked bastards pulled the bridge up behind them.
My mum, colliery town, went to "the grammar" and was well educated an got a professional job; my dad, another colliery town, went into the pit, the services and dragged himself up. A grammar education would have made things easier as far as the dragging up went.
Now rather than being able to get to a grammar, you go to your local school - and in quite a few areas there's not many good ones - and those who can buy an out for their kids.
I was lucky, my kids went to good schools (yes, CofE), and one went to a reasonable state 6th form college; the other got a scholarship to a provate school. We had good schools that my kids could go to. Some don't.