One increasingly common problem faced by social networks is what to do about death. Waiting for a death certificate and other lawyerly speed activities just adds to the misery.
(And yes, that could also mean police services could halt an account without having to negotiate with the social media company).
Social media companies may close a suspicious account down eventually, but there doesn’t seem to be a systematic way to do this independently by users.
Social media companies do, of course, keep alternative contact details for their users.