scanty not all middle class people cynically and deliberately set out to 'buy their way' into a better school by moving into an exclusive catchment area. That assumption is lazy and over-simplistic. You make it sound as though schools have a good or a bad status which is cast in stone, and the house prices are set accordingly.
I'm fairly confident in saying that if the 'best' school around just happened to be in the middle of an ugly housing estate, surrounded by crack dens and gangs, the middle classes may (just may) be applying for a place, and paying to have their children driven in and out each day, but they won't be queuing up to buy the houses.
Has it occurred to you that the root of this situation lies with the families, and not the with school, or the house prices? Good schools tend to be good because of the children in them. If a social experiment forced all schools to mix up across socio-economic divides, only then would we be able to say a school was truly good or bad, beacuse we'd be judging the value added, and assuming they were all starting from the same baseline, in terms of the intake.
Better-educated, socially responsible, self-diciplined self-motivated people tend to earn good money. They lead less chaotic lives. That enables them to buy nice houses in nice areas. They send their children to the local school. Their children (for all the reasons we know and I won't bore you with) tend, on the whole, to have fewer ishoos with behaviour, discipline, attendance, concentration, etc, and are generally more open and receptive authority, and better equipped to cope with routine and commitment.
That is what makes the school good. The pupils in it, and the high expectations of their parents.
'Fairness' doesn't come into it.
I agree it's not fair that some kids are born into challenging, chaotic, dysfunctional circumstances - life's not fair, never has been never will be. But lay the blame for their failure to thrive in education firmly at the feet of middle class parents for being able to afford to live in the nicer end of town is pointless and blinkered.