In a world where Stable Diffusion wins the copyright lawsuits, I don't think "artist" would cease to be a profession. Rather, I think the equilibrium would be artists using Stable Diffusion as a tool to automate the labor-intensive parts of making art (putting the brush strokes on the page) while the human artist provides high-level creative direction.

This would be bad for present-day artists who've invested their lives in developing the skills of putting brush strokes on the page; those skills would become worthless. But the flip side is that Stable Diffusion lets anyone make art easily, generating whatever image they can dream up, without having to spend years developing the skills first.

So even though Stable Diffusion is bad for present-day _artists_, I suspect it's actually good for _art_ in the long term. "Anyone can easily create an endless supply of art, based on any idea they can dream up" seems like a good thing to me.