The modern abuse of copyrights by the likes of Disney does not negate this otherwise wonderful institution.
Is it? We don't have the technology to duplicate the Earth in, say, 1776 but without copyright, and run an experiment, so all we can point at is a logic argument that we need to incentivize writer and artists and creators. Which I mean, sure. I want to write the next great American novel and not have to work for the rest of my life. and for my children and their children to not have to work either. Is that really for the betterment of society though? You can give some additional logic arguments in favor of that, but without Earth duplication technology, there's nothing that really constitutues real actual proof. The closest comparison we have that I know of is to look at China, which has far weaker intellectual property laws, and, well, they haven't fallen into lawless anarchy.
It's not lawless anarchy, it's just less of the works that copyright rewards (you get more of what you reward). So all those free books/music/movies that are made each year you still have, but you have less professionals taking a year off to go write their book. You have less decent funding for educations books. You have less sharing of knowledge and ideas, and I would say that makes society worse. If people were going to release it for free, they would be doing that today. People just don't work like that.
Very few creative works require kazillion-dollar budget, and presumably many of the current ones are subject to technical improvements making them accessible (you could probably produce a film/series with "1995 broadcast TV" production quality with consumer equipment today).
Copyright enables the runaway success "I made enough selling records/prints of my painting/copies of my novel that none of my children for five generations have to work." But we only say that to a handful of people per year. A reasonable grant programme could say "I can spend a couple years touring the country playing small town ampitheatres, writing my dream novel, or trying to put together a movie with friends and still be able to eat at the end of the day", to thousands of creative types every year.