Model weights, if they can reproduce something like the original, are just a form of lossy compression (or even lossless for text), where the LLM answering the prompt is a more powerful version of asking software to retrieve a specific file from a Zip archive (or a webserver answering an HTTP query) of such lossy compressed data.

So if model weights don't infringe, that would also imply that saving an image as a JPG or a video using AV-1 doesn't infringe, which would obviously effectively implies that copyright doesn't apply to images or videos on the web, which is not current law/policy, so I think that reasoning cannot possibly work.