People view copyright as less essential than patents, but the truth of the matter is that without copyright laws, there would be a significant decline in the production of movies, music, games, and many other costly mediums. Without copyright, I could legally create a competitor to netflix that paid studios nothing and played every movie ever made on any device for close to nothing. I could create a competitor to steam that distributed games and was every bit as useful and integrated, and I'd pay nothing to developers. Even if you think online piracy isn't as big of a problem as studios claim it is (and you'd be very right), the laws that keep it illegal are all that stand between today and a collapse of the content development ecosystem.
Even if copyright doesn't maximize for society's benefit because of the monopoly it creates, every copyrighted work sold is a net plus to both the consumer and the producer. Without any copyright framework, there's a significant chance that the producer could never afford to make that beneficial product in the first place. Even if you only eliminate prosecution of people/entities that don't make any money from what they're doing and allow non-profits like wikipedia to host full movies, you still irreparably break the incentive system that exists today. Maybe we don't need new movies and games, but people want them and as long as that's the case they'll want to keep protecting them with copyright.
Maybe someday, systems more like kickstarter could replace copyright, but I highly doubt it. They don't do nearly as good of a job.
That said, I'm all for much shorter terms for copyrights and the elimination of software patents.