As someone who teaches in a Grammar, you have to understand they were not intended in their modern incarnation to stand alone - they were one of three types of school in the Tripartite system.
Tripartite is a brilliant idea, but was badly implemented and run, leading to the division we now have.
Under Tripartite you have Grammar Schools for the academic, Technical Schools for the scientifically inclined and Secondary Modern for the practical.
At 11 you would be streamed into one of these, but crucially re-assessed at 13 and 16 to see if in fact you should be in another stream.
All 3 types of school would have excellent teaching and facilities, where the Grammar may have a language lab, the Technical wonderful laboratories and the Sec. Mod. state of the art workshops etc..
The idea is fantastic, but in typical British fashion it was f++ked up royally, very few Technical Schools were ever built, Secondary Moderns were poorly funded, Grammars got all the cash.
In theory, when Tripartite was abandoned all three should have gone, but Grammars generally survived and slowly the others became comprehensives.
Not all people are the same, and deserve great teaching and facilities in their area of interest, that breeds first rate professionals in all areas - but the normal thing happened and the grease monkeys of this world got looked down upon (incredibly wrongly) and the practical skills were never properly funded, rarely well taught.
Sad tale really🙁