Can you actually ask an LLM if content is AI-generated? Surely that wouldn't work reliably at all?
(Is it any wonder why people fall in love with bots that always agree with them?)
LLMs aren't intelligent. They're just very fancy math and a lot of smoke and mirrors.
So either A) LLMs are intentionally, universally making their content look AI-generated despite having the capability to do otherwise or B) LLMs cannot reliably detect AI output and their responses on the subject are complete BS.
Those are two very different classes of problems. You do not automatically get one if you have the other, in any resource constrained situation. Yes, you can infinitely iterate a RNG into a content producer given a classifier, but that presumes infinite resources.