Forcing a kid down an academic path isn't always the best option for the child. Both drama and PE teach skills which will be exceptionally useful in the real world.
As I recall, you're a teacher. And therefore, unless you're in your sixties and have a two year CertEd from the very end of teacher training colleges, have a degree, perhaps followed by a PGCE. Do you think that school teachers don't live in the real world, because they went down an academic path? What about nurses, all of whom now have degrees: not in the real world? And given university takeup is now around 40%, just what sort of presentation-giving, coaching and leadership jobs do you think the non-graduates will be applying for?
Some of those children will be university material, but the majority won't. State education has to cater for them all.
In many comprehensives, a majority will go into some form of HE. Even in those where they don't, I find the sort of inverted snobbery, which boils down to "well, I've got my degree, but the authentic working classes won't need to trouble themselves with such fripperies, as there are bricks to be laid and floors to be scrubbed" pretty toxic. I like to start from the assumption that all schools contain bright, able children who can aspire to be prime minister. Unfortunately, a lot of teachers think that the children they teach shouldn't even aspire to be teachers.
And to claim that kids should be picking up these sorts of skills in their extra curricular activities is ignoring the reality of a lot of children's lives.
The same applies to A Level Maths. Most parents can't teach that if the school doesn't.