This very much sounds like a West-only AI cartel proposal and, in fact, if you read Dario's essay - under the very telling "pacing within democracies" chapter - he specifically says he'd need the US government to issue an "antitrust waiver" for this.
The plan transparently looks like this: agree among themselves not to compete too hard, get an antitrust waiver to make it legal, and while they're at it, get Washington - under the veneer of "safety" - to kneecap Chinese competitors because only "democratic" models can be in this "safe pacing" club.
I'm not even exaggerating: Dario pretty much writes this explicitly.
There are 3 steps to his plan and step 2 is literally: "Frontier AI companies within democratic countries coordinate to establish common safety standards as well as limits on the rate of unchecked AI progress" -> the "unchecked AI progress" that would need "limits" is simply AI progress that happens outside their agreement. Another word for it is simply competition 🤷♂️
He also explicitly writes that "a key part of pacing within democracies is to keep democracies’ AI lead over autocracies as large as possible." You can't possibly be clearer than this...