Honestly, in some ways I don't think it did fully fail. I have a few twitters I keep tabs on via RSS and all of them became less active since Musk took over. The replies in the comments became more outwardly toxic than they were beforehand. While I am not sure if migrating to Mastodon specifically was very successful, I think Twitter hasn't been quite the same since the Musk buyout.
But I never used twitter besides lurk, so ymmv there.