In this version of conspiracy theory, all the labs secretly understood that training wasn't economically feasible anymore so they all jointly made it look like they were stopping for safety reasons.
Is there no end to this kind of lazy conspiracy theory
You don't need to communicate to coordinate. All these companies have the same business model, if it was financially advantageous for one of them to push that narrative, then it's financially advantageous for all of them.
Or all the big ones are content with the current status quo and willing to compete amongst each other and want to shut the door to upstarts.
You see it time and time again.
So the more likely answer is they are on the verge of making super intelligence that could kill us all?