“The Letter” was obviously self serving drivel from people who want time to get in the game. Google does care about AI existential risk, they care about beating Microsoft by any means possible, including declaring a moratorium, but continuing to make progress behind the scenes.
This guy is the real deal. I can imagine he would personally take a sledgehammer to every last PS5 and 4090. The scale of what he is advocating is so enormous and painful that it has approximately 0% chance of happening. And if he is right, we will have trained a super intelligence and unleashed it on the world before we even realize what we have done. It strongly reminds me of the black hole concerns from flipping on the Large Hadron Collider.
I doubt super intelligent AGI is possible anyway. If it were, it would be the solution to the Fermi paradox and all matter in our galaxy would be paperclips already. The Anthropic Principle saves the day.