I think you may conflate value and price/cost in your analysis. Clean water is unbelievably valuable. Parts of the world struggle to access it. Here, we think nothing of turning a tap for a glass and then pouring any excess down the drain. Abundance at low cost is a sign of prosperity and progress. Somehting we tend to take for granted, alas. However, there are markets for special water. Steam distilled water for example. This adds cost due to the lower supply and special use cases. Consider also the difference between Linux and Windows. One is free, the other is convenient. There are layers to the topic.
As for AI content and art, I suspect both will tend to fade into the background noise like disposable pop music on the radio. People who want specific art or specific prose will always want a human touch.
That said, it would be neat to see what Star Trek predicted. They can walk into the holodeck and ask the computer to generate a "mid-19th century Kansas homestead" and the computer presumably procedurally generates a representation algorithmically, similar to our AI art today but in three dimensions. That kind of quick-and-dirty creation from a prompt could be useful, too.
Such things have high value but low cost. It's related to the old diamond/water paradox where something of high value is cheap, and something fundamentally useless like a gemstone has a high price.
I hope that made sense. Non-AI replies may ramble.
I thought I covered it here:
When there is no limit on production, the monetary value of the product will approach zero.
Lots of things have value, without having monetary value. But in order to give monetary value to something that is abundant, the supply has to be restricted.
Just imagine in this world, if there was such a thing as a holodeck, how many people would leave their fantasy?
I suspect there would be holo-addicts, but I doubt it would be widespread. People were paranoid about the internet, VR, TV, and who knows how many prior technologies, too. It will be misused and abused by some, but a powerful tool for otehrs. Imagine how it could help with therapy, virtual design, and recreation.
And that easy conflation is a problem of language, and perhaps English in particular. Value is a subjective opinion held by the one evaluating, while price is an offer to exchange. When an exchange occurs, it indicates both parties valued the exchange more than the status quo.
When supply is artificially restricted, we typically have the additional corrupting influence of coercive force added to the equation, and that skews the market dramatically. The DeBeers diamond cartel appears on the surface to be an example of artificial scarcity by a market actor, but the diamond trade is at least as much a matter of corporate privilege and historical colonial mercantilism.