Indeed.
Now, music is very important to you and is a priority. Fine. But for others it will be sport. And for others art- or further maths, or foreign languages, nature knowledge, travel or first aid skills, etc, etc, etc.
In a way, this adds value to the concept of individual, eg home schooling. But on the other hand- where do you stop? Should kids have 20 hrs school days? We tried to add all this to our kids education- and we were lucky we had the skills and finance to enable this one way or another- but there are limits- both in and out the normal system- timewise and financially and with training and paying of staff, etc.
It is absolutely true that 'middle class' kids do end up with the best of both, and yes, it is totally unfair. Our kids went to the local comprehensives, and we supplemented their education to try and cover all the above.