Meanwhile, back in the private sector, a school I know well had a ‘giving tree’ where to get a gold leaf, you needed to donate £10,000 (a mere £1,000 for a silver leaf). The millions raised (in total it was millions) went towards yet another flashy building designed by a famous architect.
While I am sure such schools exist, it is also true that vast majority of independent schools are not in a position to raise millions from parents, nor do they have 'flashy building designed by a famous architect'
I visited around 10 independent schools in London two years ago when my daughter was doing eleven plus. DD now goes to one such school. The schools I visited are nothing like the one you described. None of them had flashy buildings designed by famous architects or anything like the kind of funds mentioned (I read their financial report available in charity commission website). Bulk of their annual revenue was spent on wages.
But plural of anecdeote is not data. My experience of those ten or so schools is not representative of the entire private sector. Just like your experience of that one school with a 'giving tree' is not representative of the entire sector. Choosing extreme outliers to describe a sector does not help the debate.
Part of the problem within the state sector is the opting out of a large section of the middle classes who could, if they got involved, make a transformative difference to them.
Opponents of private schools frequently say this, but my experience is quite the opposite.
DD went to a state primary that switched between Ofsted rating 'Inadequate' and 'Requires Improvement' for the seven years she was in. For most of that time we and several other parents we know had serious cocerns about very low academic ambition of the school. We could do absolutely nothing about it. I have never felt more powerless in my adult life than when dealing with the school. Then came Covid and the appalling teaching during lockdown finally convinced us to go private for senior school.
This idea that pushy middle classes can 'make a transformative difference' to schools is not realistic.
Schools, like any large government institutions immune from competition, are resistant to change and have an inertia of their own. Only those with power over them can force them to change and improve.
Parents, middle class or not, can make no difference whatsoever, beause the worse we can do is take our children elsewhere, which for a state school is of no significance.