all that proves is that more affluent areas have better state provision. Which demonstrates the point the state system is far more unfair than a tiny minority of the population going private.
To an extent, this is one of those endless circles. When I was doing teaching practise back in the 1990s, I was put in a "sink" school in Coventry. The school had a terrible reputation and therefore MC parents did not want their children to go there. Consequently, it was the school with spaces for things like exclusions, consequently people did not want their children to go there. In the end, it closed down.
DH and I have been looking at local schools for our DTDs. We looked at a grammar (the "top state school in the country"), our local comp, and then, as a teacher, I was able to compare it to the school in which I teach, which is not in an affluent area and had 40% PP students, which is more than double the average for the county (just over 16%) I am convinced that the two we looked at, who made a lot of noise about their results at GCSE and A Level, are living by their intake. Certainly the grammar needs to be doing something very wrong if it's not getting A* grades out of all its students. Similarly, the comp is in a very MC area and educational research has proved for years that the biggest factor in a child's success is parental engagement, not the type of school a child goes to, and it's indisputable that a professional working parent with a 9-5 job has more time to engage with their child after school than a parent working shifts or doing two jobs to make ends meet.
State provision is not better in areas which are more affluent - the intake makes the difference. There was nothing at either the grammar or the high-achieving comp that doesn't also happen at my school, but the outcomes, in terms of A*-C are vastly different. My school is under subscribed, despite the fact that it is a lovely, small, friendly school with fantastic facilities and the kids are generally very happy. Parents don't give us a chance - reputation is everything.