I agree, but my thought about the grammar schools was that they were ok, but the secondary moderns weren’t so good, and rather than fix the 80% which wasn’t working, we threw out the 20% which was. Typically English!
The following is a paraphrase of a comment made to me many years ago by a well-known Modeller who was once a teacher, and active in the profession during the period of change from grammar schools to comprehensives. The only group of people who really pushed for the abolition of grammar schools was not the parents, not the politicians (a large number of whom had come through the grammar school system), nor the kids who went to grammar schools. It was the teaching unions, 80% of whose members felt that secondary modern schools were not valued and that they were therefore viewed as second class teachers.
I think it just reflects that we don’t value practical intelligence as much as we do book intelligence. I have too many phenomenally clever friends who fared badly at school because they frankly never got the point of algebra, etc. I also don’t think that formal academically based education is the answer to everything. Getting a degree at 21 in most subjects simply meant one had basic qualifications for an academic career (if you got a first), an aptitude for more specialised training (if you got an upper second) or an office job (everyone else). Compare that with a 21 year old who had just finished an apprenticeship: basic training in technical skills, which would involve thinking and doing with an emphasis on the latter. Other than one route led to a minority going into research, they basically only differed in whether people ended up on the factory floor or the office upstairs.
All are equally important.