I'll leave this here:
The whole point of the Pacing the Frontier letter was that employees at both OpenAI and Anthropic are extremely aware of the risks but realize that they are locked in a competitive battle for survival between 2 companies that don't trust each other enough to voluntarily pause, while any sort of coordination out in the open might be against antitrust laws.
That's a premise, which is the point. Many (I) think the government should NOT enact regulations. For example regulatory capture to reducing competition is one reason it may not be a good idea to do what is being asked.