Earlier quoted context omitted.
Why would any fan of someones work buy a knock-off copy? We can safely assume they are a fan, otherwise why would even buy it? Also, painting is a physical object. It's a one of a kind. EDIT: your objection and many many other questions like that are nicely argued against here: https://www.youtube.com/watch?v=mhBpI13dxkI (The Surprising History of Copyright talk by Karl Fogel)
Do you think people will want to create new stories if others can undercut and sell their work for less?
EDIT1:
More than that. People don't live of royalties. Publishers do. Can people create without being paid upfront by publishers? Obviously yes. They can be paid upfront in kickstarter-like arrangement. They can be paid via donations later. They can even be paid via "retroactive funding of public goods" [0]. Or they can be never paid - just as they are today.
[0] - https://medium.com/ethereum-optimism/retroactive-public-good...
EDIT2:
Also, imagine how much good could come of long-standing IP properties owned by Disney if not for them sitting on it. Vide disaster that is current management of Star Wars.