> Why do you hold that opinion? There's a few very clear benefits to creating artificial scarcity, mostly around incentivizing creation (and sharing!) of innovations.
I think it is self evident why creating artificial scarcity is immoral, but the point you are trying to make is that from a utilitarian standpoint you think it is preferable to behave in a way that is immoral in the micro scale since it will create greater good in the macro scale. If you agree, then I don't think there's any need to justify my belief here :)
That said, I also think that it is unclear that copyright is a net positive increase to creation and sharing of innovations. The current state of monetization is not inspiring since the actual creators usually are not well compensated and money tends to stay with large corporations that are essentially just "right holders". There's also many factors that actively stifle innovation and creativity.
Patents are the most well known example, but being unable to borrow chord progressions or characters or storylines from other works is also stifling (you can't exactly release your "edanm's cut of Spiderman Homecoming" publicly, nor can you create your own sequel or alternate interpertation of the story). Quite a few fan games or fan remakes have also met their demise at the hands of aggressive copyright enforcement.
My own suspicion is that if the current models of creation will be disrupted by copyright abolition, we'll just end up seeing that a lot of the money that was spent on them will move to other avenues of funding like Patreon style or Kickstarter style funding for works. We may even see some new models created. I'd also expect that it will actually shift the balance away from large corporations (whose primary value is having lots of money that allows them to hoard rights) to smaller creators which will now have more direct funding available to them.
I also think an interesting case to look at is Video Games, where the concensus is that a game's mechanics aren't copyrightable, and so whenever a new interesting Indie game comes out on steam, there is a rash of other cool Indie games with their own takes and remixes of the same concept, like the glut of Roguelike deckbuilders after Slay the Spire or the current glut of "Vampire Survivors"-likes that have their own interesting takes on the core idea. Eventually when there's enough buzz around such ideas they can even penetrate the AAA sphere (where adding "Roguelike" elements has started to appear slightly). It is also quite common to see games that are in Early Access for a very very long time, essentially letting the community fund the future creation and expansion of the game.
> If we can't create artificial scarcity around ideas, then ideas are in a sense less monetizable than, e.g., creating a piece of furniture. But this is just an accident of the way the world works - I can physically prevent you from taking a chair that I made, but I can't prevent you from taking an idea I had. Why does it make sense that the world works this way? Isn't it a whole lot better to encourage innovation, vs. encouraging more people to make physical objects, just because those are inherently scarce?
So as I said, I'm not sure it really will make ideas less monetizable (or that if it will, that it will do so significantly). Even today I can get any video game I want for free (illegally, but that effectively doesn't matter since no one will persecute me for it), and yet I still buy video games. In fact, a strong reason for why I buy video games today is because as a child I had a friend that had easy access to pirated CDs and I'd play a lot of games at their house, fueling my passion for them.
And relatedly, it is no accident that "software is eating the world", it is exactly because it is so easy to share, the low marginal costs make it easy to have a strong worldwide impact without too much real world effort :)