Hypothesis (unlikely): Musk is pushing so many people to create Mastodon accounts that the communities/servers here will be overloaded, thereby creating a retreat to the "reliability" of the centralized service. More-evil hypothesis would have his friends overseas (in Russia, China, e.g.) launch DOS attacks against major Mastodon instances, for same purpose.
Interesting-- and even if the Musk part of your hypothesis is unlikely, the prospect of various types of attacks seem very likely (attacking ALL the small and the large instances b/c why not, w/ automation?)
I am glad to see so many infosec people on here!