There's a famous Carl Sagan quote: “If you wish to make an apple pie from scratch, you must first invent the universe” which hints at the problem: Nothing is created in a vacuum.
Let's compare what Stable Diffusion does with what Franz von Holzhausen, head of design at Tesla, does. Franz didn't come into existence out of nothing and knew how to design cars. Instead he studied transportation design and worked at Volkswagen, General Motors and Mazda before joining Tesla. All these steps trained his (actual) neural network with inputs from copyrighted car designs.
Based on these inputs he was able to create the designs for the Model S, Model 3, Model X and others. Does this mean that Mazda can now levy a copyright lawsuit against Tesla? It could, based on the reasoning employed in some of the Stable Diffusion suits, but it won't based on the lack of similarity between the cars of both brands.
I believe that the law around AI will come to a similar conclusion. AI learning is neither fundamentally add odds with copyrighted material, nor confirming it. It will be a matter of degrees of derivation - how different is the output of the AI from its copyrighted inputs.