"Let society figure out how to remunerate artists without coercion."

It already has. It's called Spotify, Apple Music, etc. If you remove copyright from the equation, this is what will happen:

These services will continue to exist, but free of copyright restrictions will make all content available to their customers. Then they'll become free, or freemium with an ad-supported free tier and an ad-free tier for a few bucks a month. Now that one of their major cost centers is gone they won't need to charge much.

Apple and the other Lords of the Brand and the Distribution Channel will still pay the artist... whatever they see fit to pay. It will be below minimum wage, with the artist expected to make up the difference by brewing coffee or waiting tables. They may occasionally take an artist and make them wealthy (by artist standards) in order to con the majority of punks into thinking art is a viable career path. As with all industries powered by burning out the young, you have to keep the queue full.

This looks not terribly unlike the old record company model, but with one key difference:

In the old model the artist had a contract. It might have been a shitty contract, but it was a contract and the artist had some negotiating capability. In the new model the artist has none, zero, nada. Yes master, pay me whatever you like master.

A few artists will try to rebel and form alternative channels, but there is no copyright, remember? Apple and the others will simply vacuum up the content from these channels and add it to their already-massive catalog without paying anything in return. A few loyal fans might boycott the big channels and go with the indies, but not enough to make a difference. Do you want six apps/sites/feeds to listen to music or just one?

A few rebels might also try to turn the tables by vacuuming up the catalogs of Apple et. al. and creating bootleg ad-free versions. Sure, fine, go ahead. It'll cut into the majors revenue a bit but it won't do anything for the artists. If anything it'll make things even worse by squeezing the majors, causing them to cut expenses in the one place they're now completely free to do so: paying artists less.

It's called a "deflationary race to the bottom," and in such scenarios the lower-downs lose more than the higher-ups because they have no intrinsic structural leverage.

If you're curious I can also tell you what will happen without child labor laws. It'll involve crying, secret mass graves, and cute little amputees.

Everyone is not an asshole, but enough people are assholes and enough businesses are more or less amoral that laws are required to address the worst of the resulting excesses. You'll never have a society without coercion. The question is whether you want one where the strong coerce the weak or one where coercion is applied according to some more objective standard and with the goal of common welfare and compassion. What we have now is somewhere in between, as real things tend to be, but I'm very much against anything that moves it more toward a might-makes-right world.

I say this as an ex-Libertarian. The big thing that destroyed my faith was getting deeply involved in the business world and learning how Shit Really Works, which reminds me of that old 'we should teach the Bible in school so we'd have more atheists' line. It ain't a joke.