The idea is a simple one: Fifty years after a work has been published, the copyright owner must pay a $1 comment maintanence fee. If the copyright owner pays the fee, then the copyright continues. If the owner fails to pay the fee, the work passes into the public domain. Based on historical precedent, we expect 98% of copyrighted works would pass into the public domain after just 50 years. They could keep Mickey for as long as Congress lets them. But we would get a public domain.
A step in the right direction. Even better if the fee doubles every year thereafter, but that can come as an amendment later.