I don’t like the clickbait title at all – Mastodon’s clearly going to survive, at least for the forseeable future, and it wouldn’t surprise me if it outlives Xitter.
Still, Mastodon is struggling; most of the people who checkd it out in the November 2022 surge (or the smaller June 2023 surge) didn’t stick around, and numbers have been steadily declining for the last year. The author makes some good points, and some of the comments are excellent.
You would be able to find them if every instance didn’t decide to defederate with Threads.