I see you are in Britain, where copyright originally developed. As I recall, the history was a couple of publishers trying to bloody each other (1). It had nothing to do with whether a merchant wanted to transcribe copies of Hamlet to share with friends practising for the local theatre production 50 years after Shakespeare's death. The principle profits had already been wrung out.
In the US, the copyright exists To promote the Progress of Science and useful Arts (2). It essentially is allowed to exist with the hopes that on average it will further the common good, but it is limited because even at the time, there was a good deal of skepticism about that monopoly power. With regards to music and the visual and performing artists, I think many might actually argue that they are expressly uninterested in meeting the definition of "useful": "Art is art and everything is everything else." (3). But even if we offend them, it must surely be useful to lower the cost music in the air. It must surely be in the public good to reduce the cost of happiness.
I would be interested in hearing why you think right is what you think it is, your understanding of the history of where copyright came from.
