Where I live we have the lottery allocation system so we don't have these 'acceptable options' you keep referencing. Equally, why are you thinking in such extremes most state schools are not 'sink' schools and yes of course they have middle class children attending them. I have a very good insight in to private school life and I really, really know that it is not something I'd ever want for my DC.
I've not said most state schools are sink schools.
Like I've said probably half a dozen times now, I've seen the excellent, the good, the bad and the ugly in the sector and have worked across a range of catchments.
A school doesn't have to be a sink school to have issues that affect children's experiences and education in a negative way.
You only have to look on a number of threads on here to find parents who are finding it incredibly difficult for their children to have the required adjustments put in place for their child's SEN, or where bullying hasn't been dealt with effectively, or where their child is falling behind because they've not had a stable teacher for a long period of time. Then there's having a child has allocated to a school that is more bothered about flattening the grass than supporting children who don't fit in a neat box. Or the parents who are really struggling because their child has emotionally based school avoidance because they are really unhappy in their current school and when they're asking for help they're told the wait list is huge. Or the children who want to do well, but find that because they're low prior attaining they're in a set with other students who want to misbehave and it means those who really need some additional attention can't access it, but it's ok because the other classes will probably keep the school's Progress 8 score high enough not to draw attention to it. And there's the very bright children who need to be stretched but because they're probably going to get 7s and 8s and keep the spreadsheet looking good, they'll be largely ignored in most of their subjects.
Will there be children in all those schools who thrive still? Of course.
Will there be children in all those schools who do well but their parents have also spent money on tutoring to plug the gaps from the issues in the schools? Of course (and the bonus here is then the school results look great too on paper)
Will there be children who do ok but probably don't reach their potential? Of course.
Will there be children in those schools who are let down and suffer as a result of the situations they're experiencing? Of course.
Until I've walked a mile in someone else's shoes I'm not going to be patting myself on the back for the decisions I make for my DC.