http://debashishbanerji.com/creativewriting/poetry1/makoto/ There’s a battle going on in the UK trying to extend music copyrights longer than the 50 year term originally imposed. Musicians argue that they need the money that copyrights create for them, and that without longer copyrights they’ll have no incentive to create new music.
It seems to me though, that the opposite is more likely. These musicians created songs knowing that they’d continue to recieve royalties for 50 years – so it was enough incentive for them originally. In addition to that, it seems to me like having your income run out would be a great motivator to create new songs that you could earn money from.
Copyright isn’t intended to be a system of making sure musicians continue to recieve royalties for stuff they did 50 years ago. It was designed to encourage innovation, and discourage copying and ripping off.