There are pupils who can be described as being given A on a plate , although it is not so much that they are handed anything but just academic success comes easily to them. My DSS achieved straight A at GCSE ( as far as I can remember ) and is on track to achieve similar at A Level. He has hardly broken a sweat.
My own son is on track to do similar at GCSE simply because his special needs mean that he has a photographic memory and he doesn't socialise much so studying is no hardship .
I would imagine top selective schools are full of students like this, not exclusively so but they will be there.
For what it's worth I imagine my stepson is going to get a huge shock at university - or at least I hope so.
My second daughter has to work much harder to almost achieve the same .
All of my children at state schools are surrounded by other aspirational children and families .
I think there is a tendency to compare the worst state schools with the top independents .
I am not going to claim that my children's comprehensive or even my son's grammar can compete with the top independents in the league tables. But I do not think that my children would have done much better at an independent . The only way they miss out is not having the same level of sports or extra curricular activities on site. But we can provide that for much less than £100k a year and we get to support our local schools .