If the tech is so dangerous that a closed market is necessary, then maybe it should be nationalised.
PopeGPT debating آیت الله-GPT about theology could be interesting; but do you want to wake up to the news that советский-GPT is running a successful propaganda war in the USA and now the American Communist Party is likely to win the next presidential election? That ChatKimJongUn is successfully boosting the industrial capacity of the North despite sanctions?
That's why international agreements are also relevant, even if you don't share Yudkowsky's fear of alignment failures paper-clipping everyone.