Derivative work or transformative? It's not the same.
AI works also clearly aren't transformative in many cases. If you ask it a question about a paper, it'll quote bits of the paper at you. That serves as an exact substitute of the original work. If you ask it for song lyrics, or information about the news, its content is a direct substitute for the original source it was trained on. This clearly does not fall under a transformative use case
You could argue that some uses of it are transformative, but even then - its easy to find some piece of training data in the source code that the output work supersedes. By its very nature it does not have the capacity to genuinely invent under the law (as it is not human), and a prompt isn't a significant enough part of the processing to count here