I know what the Pareto principle is, and I don't think 20% of users will pay this subscription fee, that's a pretty wild assumption

Go to a museum. Talk to people who have studied art, people who have bought art, people who have made art.

I suspect you'll find that the value humans put on art (monetary or otherwise) is NOT based entirely on the visual aspect or the "quality" of the art, but is mostly having to do with the circumstances of the artist, the circumstances of the time and the situation that art was made in, and what the art says about people and society and the human condition. AI can replace stock photos, illustrations in some cases. AI cannot replace creative endeavors entirely - at best if we ever have truly intelligent AI it could contribute with art from a wholly new perspective, but that wouldn't invalidate art made by humans.

As a personal example: I saw the Turner exhibition at the Boston MFA this summer. Turner was an English painter, lived 1775-1851. His most famous works show how life changed with the industrial revolution. You could feed a prompt of "english coastline with sailing ships and a steamboat" but you wouldn't end up with something as interesting as made by the person who was actually around at that time. You could generate a painting from the prompt "a ship visible in the background, sailing through a tumultuous sea of churning water and leaving scattered human forms floating in its wake" but you wouldn't get Turner's The Slave Ship from it.