Dario has been writing long-winded essays like this since long before AI existed. I strongly doubt he's the type of person to delegate it to AI now.

"Pacing the frontier" sounds like something that was carefully wordsmithed in committee, to avoid terms like "slow-down" or "pause" that sound much more negative. They probably did ask an LLM to generate a list of options, because why wouldn't you? But the rest of the writing is almost certainly just Dario.