WordFactory: If Music, Art, PE, Religious Studies etc are no longer given equal weight to other optional subjects, the resources channeled into them will decrease, and the educational value of the courses will therefore be diminished until people decide that they're no longer worth studying. And what's next: English Literature? After all, most kids just need to be able to write business letters, reports and e-mails, not wax lyrical about the aesthetics of Keats and Shelley - the latter is a luxury, not a necessity...
I think this is a very dangerous path to set out on. It moves state education closer to becoming a production line which churns out skilled, compliant, and dogmatic workers rather than creative, analytical, and independent thinkers. More importantly, it threatens to strip away the lifelong solace which "soft subjects" can provide to those who aren't academically gifted or socially advantaged. Long after a "bright but hopelessly disadvantaged" student from a sink estate has forgotten his trigonometry and settled into a lifetime of stacking shelves in the local supermarket, his life may be enriched by his enthusiasm for music, or his love of WW1 poetry, or his skill in drawing, or his appreciation of abstract thinking and debate. Yes, qualifications are very important, but I believe that "soft subjects" are essential because they help us to exercise mental freedom and find beauty and value in the world when everything else has been taken away from us. Surely poor kids need that mental autonomy more than anybody else?
Sadly, we don't live in a culture which makes folk dance, music, poetry etc universally accessible any more (mostly because there is so much money to be made from charging people to access them), and so schools have to compensate by offering a more structured form of engagement with the arts as part of formal education.
Also - wouldn't you say that cultural capital is pretty much essential for social mobility? I have a really strong 1st in English from a RG university, numerous prizes for my subject, learned to play an instrument well enough to teach others, and was brought up to prefer live music and drama over any other form of entertainment. I have a good vocabulary and have never been shy. However, when I was invited onto a special programme for high achievers at my university, there was an extremely pronounced gulf between the few students like me who had gone to pretty average state schools, and the more privileged students who had developed an "aura" through years of debating and amateur dramatics. I wasn't exactly intimidated by it and I refused to let it make me feel inferior, but it did make me realise how much more there is to social mobility than qualifications...