@Morefreedomless11plus my point is that you can't assert links between disparate facts which are not causative.
Yes, obviously, a child that doesn't get a place at a selective school having taken an exam at 10 or 11 may nevertheless work hard in a non-selective school and go on to university and thrive there.
Yes a student that gains AAB at a poorly-performing state school is probably going to do better at university than a student who got AAB at a selective and well-resourced private school, because the former student needed higher intelligence and harder work to get that AAB and might well have got A A A if they had been granted greater educational opportunities, whereas the latter student might have ended up with BCC grades if they hadn't been nurtured and challenged by the private school.
None of these facts are valid arguments against the 11+ exam itself. The vast majority of children in the country don't take it at all - it is only taken by those living in the now fairly rare state grammar areas, and those whose parents are hoping to get them into private school, so a vast number of state schools will contain a significant proportion of kids who would have passed the 11+ if they'd taken it.
Certainly any child who doesn't get the school offers they are hoping for following an 11+ test should not be discouraged by that. We have just come out of this uncertainty ourselves and what I told my DC was "All that matters is that you do your best, and whatever happens I am going to be proud of you, because trying your best to achieve something difficult and not managing is just one step in a long journey which will have lots of ups and downs, so one thing that goes wrong or goes right isn't a big deal"
Good luck to you as you wait for your outcomes - I know it is very nervewracking!