I think, broadly speaking, you can identify a handful of guiding principles, drawn from various theoretical approaches, to justify why copyright exists. Among those are providing an incentive for the creation and dissemination of works by ensuring that authors get rewarded. However, I think it's absolutely critical to maintain or to keep in mind that this principle has to be balanced against a broader communal and cultural interest in ensuring the free flow of ideas and cultural expressive activity.
The challenge that you face, of course, is finding a way to calibrate all of the various interests and various mechanisms that you're putting at play here to achieve those quite disparate functions. There's a tension at play there. It's an ongoing tension.