I don't think you need to be an ML researcher to understand his point of view. He wants to do fundamental research. Optimizing LLMs is not fundamental research. There are numerous other potential approaches, and it's obvious that LLMs have weaknesses that other approaches could tackle.

If he was Hinton's age then maybe he would also want to retire and be happy with transformers and LLMs. He is still an ambitious researcher that wants to do foundational research to get to the next paradigm.

Having said all of that, it is a misjudgement for him to be disparaging the incredible capabilities of LLMs to the degree he has.