hope the rest of the fediverse can continue to grow organically

I think this is where our hopes and pessimisms diverge. I simply don't think that right now mastodon can grow organically anymore. Threads has come out as an anti-Elon option for Twitter and already has tens of millions of users. If people are now looking for Twitter alternatives, why would they think twice about mastodon? On the other hand, if they do join Threads and some Mastodon instances are federated, they could find out about the fediverse and move on to using those instances without really affecting their day to day use. Inversely if the fediverse walls itself off from the start, there is no incentive to join Mastodon anymore since there is a much bigger alternative with all your friends and people you want to follow.

Sure the betrayal of Threads is pretty much inevitable, in one way or the other, but if the fediverse can become a viable alternative in the minds of Threads users before that, a much bigger migration could be seen than with twitter now. The aggregated added growth from having been federated, together with a final push from a mass migration should be enough to set Mastodon up as a viable competitor.

Of course this is just about Mastodon/Threads. I think Lemmy could have a different approach if some Reddit alternative wants to federate. This is because Lemmy/Reddit is more about the total content quality (and quantity) rather than who is making that content. With Twitter/Threads/Mastodon most people want to follow specific people. That's why walling the whole Mastodon away from Threads is, imho, a mistake. Of course it's also a mistake that, due to the nature of decentralisation, could practically never happen. There will always be instances that decide to stay federated, even if all the big ones do defederate.

There is one big threat that I do see, and that is if a company would take over the development of activitypub, Lemmy or Mastodon. This should never be allowed to happen as it would allow closing the source, or parts of it, and then just pulling support. As long as the development stays open, the worst that could really happen is that we'd need to move to new instances that do defederate.

But, like, how?

So you’re Meta, and you want to Embrace, Extend, and Extinguish ActivityPub. Maybe you add some new nonstandard feature that’s not compatible with existing Mastodon clients. Annoying, but are people really going to sacrifice everything they like about their favorite client so they can take advantage of some random proprietary feature?