There is a possibility that everything we output is merely a regurgitation of thousands of human answers, ideas, and thoughts we have encountered before. Including this comment of yours. And mine.
It's trivially false because ChatGPT was trained on something (in this case, Stack Overflow), which, in turn was trained on something else (maybe a book), and so on. So knowledge, imagination, and genuine creativity must exist somewehere down that chain. Everything can't be just repeating what was learned prior ad infinitum, or we'd have nothing new. Ironically, even the development of large language models is an exercise in creativity.
The real question that'll soon dominate is, "How can we even tell the difference?"*
(* - Reworded with ChatGPT 4)
For example, there is no intrinsic value in something new. If I take a new solution to a problem, lock it in a box, then it has zero value. It is not improving anyway.
Now, if I take a solution and present it to you in a manner that you can understand, that has an inherent value to the end user.
By this analogy attempting to say that LLMs are useless because they only know what already exists is far to harsh of measure because the vast volume of human output is rehashing what we already know.