Sept 2024 was when OpenAI announced its new model - not an LLM but a "chain of thought" model built on LLMs. This represented a turn away from the "scale is all you need to reach AGI" idea by its top proponent.
If September 2024 marks the date in your mind stagnation was obvious, surely the last improvement must have come before?
Whatever the case, there are open platforms that give users a chance to compare two anonymous LLMs and rank the models as a result [1].
What I observe when I look for these rankings is that none of the top ranked models come from before your stagnation cut off date of September 2024 [2].
