Correct me if I am wrong, but as I understand it as long as they do business in the US then they are accountable to US laws/regulations.
The other interesting element is that the most vocal crypto backers, often for ideological reasons, want to deal with this completely unregulated system that crypto has created. If the SEC had intervened before FTX collapsed, I'm sure you would hear cries of "authoritarianism" and "fiat banks are scared" from the usual suspects. Perhaps we should let these people have what they want - consequences and all - and just limit the ability to buy Super Bowl commercials in regulated markets for unregulated products.