There wouldn't be an LLM startup ecosystem without big tech.

Notable contributions: Nvidia for, well, (gestures at everything), Google for discovering (inventing?) transformers, being early advocates of ML, authoring tensorflow, Meta for Torch and open sourcing Llama, Microsoft for investing billions in OpenAI early on and keeping the hype alive. The last one is a reach, I'm sure Microsoft Research did some cool things I'm unaware of.

You might be right, we don’t know how an alternative reality would have played out though to say if this is the only way (and fastest) way we could have got here.