From an economic perspective:
The copyright system is designed to give some market-based financial compensation to people who create works (and people who distribute them -- publishers)...
BUT *without* giving them the extensive rights to prevent the use and reuse of those works by the public and the authors of the future.
The government recognized that creators need compensation in order to create...
BUT that the ultimate goal of spurring that creation was to benefit the public.
The Constitution is quite clear about who Copyright was *ultimately* supposed to benefit. (The public!)