They’re not done yet. Just announcing (and the verge reporting on it).
Their announcement (here) is quite forceful though, interestingly. The article described it as a manifesto.
See also a recent post here about their survey on integrating activity pub: https://lemmy.ml/post/14734757
Ghost itself is one of the bigger winners in the oops-Substack-has-Nazis newsletter migration, and letting authors on its platform more easily distribute their work is itself in stark contrast to Substack, which is reacting to its failing business model by making it harder to leave its own increasingly-social-network-like platform.
a synopses of this Verge piece by the autotldr bot Lemmy bot