Vocational subjects can at least be done to the same, if not higher, standard outside school with relative ease.
I suspect very, very few children heading for a career in music, drama or dance are relying on the two lessons a week at GCSE.
The huge emphasis on STEM also means that those children better suited to vocational, or more literature based subjects are also massively restricted in their GCSE choices.
I did 3 languages for GCSE which have been a lot more useful in life than Chemistry would ever have been.