So the basic story would be that mastodon's dominance is pretty entrenched and the "migration" event is mostly "over" (whatever other "events" are on their way)
But I wonder about the details of the firefish moment
I think it revealed that there are/were plenty interested in novel & different platforms. We're novelty seekers after all right. Generally, I'd wager any new platform needs some degree of novelty to "make it".
Further, its collapse showed how hard creating a new platform is.