Found this post super informative as it relates to Mastodon, and thought Lemmy might also benefit from this perspective. Iโm not sure I share his optimism, but his points seem sound to dampen some of the alarm bells over Meta joining the Fediverse.
Google effectively killed XMPP this way. During the time the federation was working the protocol essentially stood still, because they were afraid of breaking GTalk. Once GTalk gained enough momentum Google just pulled the plug.
https://ploum.net/2023-06-23-how-to-kill-decentralised-networks.html