Then how should any artists make any income at all from their work? I'm not talking about 0.0001% lucky creators with huge compensation. I mean the 70 year old with cancer who cannot write anymore. I mean the 35 year old disabled artist who cannot work a "normal" salaried job. I mean the artist from an underdeveloped country who became popular and now the "wealthy" countries want to translate and publish their work in their relatively wealthy markets. [These are all real cases I'm familiar with, as a person who actually is in community regularly with working-class authors.]
The world in which you speak of where art existed outside of notions of intellectual property meant only the wealthy and well-connected could be artists, whereas with copyright a cancer-fighting, aging, midlist author can still demand royalty payments if Disney bought his books and are still selling them for profit (Alan Dean Foster, specifically). Peter S. Beagle (The Last Unicorn author) was put through elder abuse and lived in poverty, and only many years later was he able to regain rights to his work back as well as force recompense for harm committed to him- this wouldn't work if the rights to his work expired while he was being abused.