> are capable of evaluating the LLM's output to the degree that they can identify truly unique insights

I noticed one behaviour in myself. I heard about a particular topic, because it was a dominant opinion in the infosphere. Then LLMs confirmed that dominant opinion (because it was heavily represented in the training) and I stopped my search for alternative viewpoints. So in a sense, LLMs are turning out to be another reflective mirror which reinforces existing opinion.