DH failed the 11-plus, and he felt so angry he worked and passed the 13-plus and went to a technical high school.
I didn't take the 11-plus, but both the 9-plus and the 10-plus and the entrance exam for a direct grant school (gpdst). I passed, got offers of a place at a grammar school, grammar school place at another direct grant school, and then an offer of a fee-paying place at the school where I sat the exam. We were outside their very small catchment area for a free place, but later got one when my father's income dropped off the bottom of the scale.
Interestly the local council was always lab controlled and in the sixth form told my parents I was entitled to free school meals. For some unknown reason, I had been ever since I had gone there, they had just never been told.
I chose to go to the direct grant school, and enjoyed it, but could not be described in any way as one of its 'shining lights'. Going from a school a mile and a half away with 150, to one 9 miles away with 800 I felt rather lost, something I think experienced by many.
At the time there girls who were sorry to go to the gs, the head was completely round the twist, being known as Nutty Norah, and others who were glad to go to the comp because it was newly-built.
Some children will be more in tune with an academic education, others with a more technical one, others with a more vocational one. What I think is really important is that ALL children get a really good grounding in maths and English, before going on to the secondary education that is most likely to benefit them, not their parent's aspirations. I mean maths and English - not 'literacy' and 'numeracy' which, sadly, seems to have led to many having no real skills in either.
What many have failed to recognise over the years, is that children at the top end of the intelligence range have, in some ways, the same special needs as those at the lower end, but are often overlooked because they can 'manage'.