Besides, if LLMs only recycled training data with no changes, they'd just be really bad search engines. Generative AI was created initially to improve training, not for human consumption - the fact that it did improve training shows that the result is greater than the sum of its parts. And since nowadays they're good enough to pass for conversation, you can even observe that on your own by asking a question that doesn't appear anywhere on the training dataset - if there's enough coverage on that topic otherwise, I've seen them give very reasonable answers.