Now that's not to say that such a system would be undetectable by any possible adversarial technique. The Turing test is not unambiguously defined, but my definition would have it conducted with average well-educated people not specializing in AI and not having special knowledge of adversarial techniques for the specific machine being tested.
As much as I admire Turing, I don’t think this particular idea of his was a sound one- an intelligent computer is not human, and lacks a human brain. It should be expected to be better at some things, worse at others, and overall noticeably different… even long after it exceeds human intelligence levels.
It's actually scary to me just how smart Turing was because he immediately recognized, at a time when computers barely existed, that the real test isn't if a machine can play smart but if it can play dumb. Because that eliminates all the parlor tricks and requires actual reflection. Just mind blowing to anticipate that in 1950.
A human mind, for example is not sufficiently generally intelligent to convincing mimic even a fish mind- we cannot generally emulate minds structured differently from ours- e.g. humans cannot actually do the meta task your concept of the Turing test expects AI to do. Even an actual human mind with vastly different experiences- simulated perfectly in a computer or even just a regular person from a very different culture will fail your concept of the turing test, because our mind is shaped by our experiences.
Also, I think your conception of LLM limitations is mistaken. We don’t fully understand them in theory- but I think the way to think of LLMs is that they are a probablistic world model able to simulate almost any scenario if setup properly. They are not themselves a mind, but if sufficiently good, they will simulate minds- and those simulated minds are actually minds but not human minds. Noam Chomsky published an article arguing how LLMs were incapable even in theory of doing things GPT4, which was released shortly after his article can do- showing that either his model of what they are, or of what is required for those tasks is mistaken. Ironically his way of thinking involves failing to understand that intelligent minds vastly different than human minds are even possible- while expecting AI to be able to not just understand but correctly navigate that situation.
There has been some odd people fooled by computers since the 70s, and 10 years ago we had competitions where the best hint people claimed they had was if their interlocutors were good at math or not.
It was clear 10 years ago that the Turing test would be beat soon.
Similarly, today a lot of people think we are eons away from useful general purpose robots, but it is clear to me that they are coming soon.
Honestly, I wasn't even that well informed to make my own. I kept postponing looking at the chatbots until after it was beat.