“But clearly the difference between LLMs in 2025 and 2023 is not as large as between 2023 and 2021.”

This is a ridiculous statement. A simple example of the huge difference is context size.

GPT-4 was, what, 8K? Now we’re in the millions with good retention. And this is just context size, let alone reasoning, multimodality, etc.

I don't think that refutes the point. I'd readily agree with the parent that in terms of actual usefulness and efficiency gains, we're on a trajectory of diminishing returns.

Gemini’s 2M context window is kind of a gimmick and not useable in practice.