My answer on Quora @ http://qr.ae/GyVBh
Great question but I believe it dilutes the intricacies of IP law. Selling a product isn’t the same as creating a song. With that said, I’ll look at the question from a creative perspective (i.e. music/movies/entertainment) = copyright law.
Consumers/Community
The entire infrastructure of intellectual property law is designed to bring the cost of all creative products down, eventually close to zero, where it’s best able to serve the most possible consumers. However, for example, giving away free music doesn’t motivate an artist to create better music. The intent of copyright law is to create a marketplace where consumers can buy an artist’s work based on the utility the general community assigns to the work.
Artists
Copyright law – 1) improves the collective creativity/intelligence of the community and the community celebrates the artist’s genius and 2) provides a financial incentive for artists to pursue new creative endeavors. Artists are motivated by the fame (1) and the money (2). Even with the internet, there is still money to be made and recognition to be had. The fact that you can create a song and the duration of rights last the musician’s life plus 70 years tells us that it is lucrative business if an artist were to make great work. It costs money to make art but the dreams of fame and money certainly will drive people to continue to make art so long as there is some monetary award and society keeps celebrating the particular art. The circle of art?