Hi Green: wishing you all the best with your forthcoming choices!
I am going to give you my anecdotal (and therefore, limited) experience, but much of it concurs with above PPs...so many different reasons why people get additional support for their DC, irrespective of where they school.
My DD needed help last year. Like an above poster, her confidence was shot to bits on a subject: maths. Not because she wasn't good at it, though maybe has an arse about face way of learning, but her teacher was just too fast for her, didn't explain well enough, didn't go over wrong answers etc etc. She's in a school that last year over 50% of DC got a 9 in maths, so pace is fast. And she felt stupid against those that 'just got it'.
She kept avoiding the offer of outside help (I couldn't). Her teacher kept saying she didn't need any, all was fine. I eventually had to kick in and got a mentor (a sixth former support that her school provides when needed) and after 2 terms, she was solo again, back on track, declined a move up to top sets (because she didn't want a repeat of previous year) and is now comfortable, helped by a different teacher who she loves.
Was this intervention a tutor? Of course it was. Non-paid, but nevertheless the same result. It would be great if every school had great teachers that were able to adapt their style to individual students' needs, but reality is some just don't/can't. Had it not been maths, I would have helped her to understand you don't have to be an ace at everything. If there is rife tutoring throughout many subjects (exc maths/english) at her school, I don't know about it, and for those that are, then I am sure they have their reasons; though often these started well before entry at 11, where maybe the school wasn't the best match in the first place but they managed to prep their DC enough to get through.
The challenge I have is that parents always think this is solely the school's fault, that the school, somehow, is responsible for not reaching top sweep of grades, even more so if you are sending DC to stellar grammar/indies/comps. it does not seem to be ok anymore for there to be the grades from 8 (or worse, even 9) down?
We need to be careful what we wish for, as parents. By the very nature of choosing highly selective schools, the bar will always be high, and for some DC (and their parents), not achieving top grades is the be all. Not whether the school is a match, that would their DC really enjoy the 5 - 7 years there because of a bunch of other stuff the school does, how does it help young people be more rounded etc. And as more prospective parents coming into 11+; look at league tables alone and question why the marginal differences year on year (where a better guide could be to look at the leavers destinations/courses gained?)
Long way of me saying, there will always be the 'friends' telling you stuff. That some of it is true, some of it has reason, some of it is because there is a keeping up with the Jones and not accepting anything less that top (when they'd probably have gained top anyway without tutoring). Post GCSEs more independent thinking is necessary so if DC are still needing additional support at that stage, maybe a re-think of destination outcomes are necessary, but who knows the individual circumstances, really?
In summary, the very nature of top performing schools is going to have an underground of additional support, from those parents who feel their child's 90% is not good enough against Child B and C's 100%. And DC who will feel like that, irrespective of how much the school tells them it's ok, unless they have parents who also agree that it's ok...
Sorry, that was long! I've rolled in all your questions from other threads into one! And wish you all the best too...