This isn't a great argument. Researchers who do not think string theory is good are not going to spend years on it. There are plenty of experts that dismiss string theory. I have no skin in the game, and don't care either way, fwiw.
Our grandparent is sort of the perfect example of an insight-free comment: confidently claiming string theory is useless (without supporting evidence) and then claiming (more like imagining, since there's again no evidence provided here) that an LLM would have abandoned such a research program long ago. What's there to discuss? The comment is based on a made-up scenario; it is, in other words, pure fiction.