Unfortunately if the frontier labs that care about safety stop or slow down unilaterally, that doesn’t make the problem go away. It makes it worse when labs that do not care at all about safety, or deny that it is even a problem, are leading the way. That’s why there’s needs to be some form of international regulation.
Incidentally this regulation won’t really touch the US providers - at least it sounds like that’s the plan if you listen to current US admin