Thats the wrong premise for this discussion.
An artist that paints a picture and sells it or performs a concert and sell tickets is a very different thing than someone who mass-produces posters or record a song once and sells it.
And so you need to look at this from two very different perspectives to understand whats going on.
An artist who make songs on Spotify available is nothing more than a businessman trying to sell a commodity as if it's a scarce resource.
An artist who sell a painting can decide what price they want and is in many ways the extreme capitalist having the potential to sell a product that is completely disconnected from the labour that went into making it.
The reason why we have copyright is so that I can't sell someone elses work as if it's mine and that has nothing to do with post scarcity, basic income or automation.
Successful artist are successful business people. Nothing more nothing less.