Remedy is painfully obvious: make an example of Twitter and pass laws that holds platform operators liable. That should fix all sorts of security problems.
Company X presents the public with communications of known public figure. Company X assures the public, via a blue checkmark, that said communications are from a "verified" account.
Shouldn't company X be liable if someone other than the known figure is making public statements?
It seems logical, fair, and a societal 'good thing', that company X should either let go of the pretense of "verified" communications, or get its act together, or pay the legal price.