There's been lots of discussions about this already, but the short version is that this is a play book tactic used by big companies to take over a sector.

I didn't experience this at the time, so the details might be off, but one example, as I understand it, is what Google did with Google Messages a decade ago or so. They federated using some other service that existed before Activity Pub I think, and most casual users just flocked to it with no idea about any federation. Once it got big, they just stopped federating, and anyone who was not on Google Messages but had friends who were (which most did since GM was so popular) had to change to GM.

Other similar such things have happened before with other products and in other markets, and that's what people fear will happen with threads.

Except reddit or lemmy doesn’t have a big concept of persistent friends or connections.

Why would you care where some random moves to? I don’t know anyone here and no one knows me. That’s the beauty of it. That’s why it’s different than other platforms and past occurrences.

You don't need the friends, that is just one example. You have to think of the general concept and logic; Lemmy, as well as kbin, have communities. If one place manages to secure all or most major communities, they can pull the same thing. And Threads is meant to be a Twitter replacement, so you do have the bit about connections, as well as influencers. It's like Mastodon, but completely centralized.

So the same logic applies: if Threads joins the Fediverse and most people go to Threads, then most users who are not on Threads will still end up having a lot of discussions on Threads and following a lot of people there. Then some day, once Threads gets big enough, it will stop federating and Fediverse users will be forced to move if they want to keep those connections. Meanwhile, Mastodon dies. Lemmy and kbin might survive because they fill a different niche; however, if instances start federating with Threads and making it possible to follow people on there, then the same exodus will happen.

We can learn from history, or we can let it repeat itself. Federating with Threads would mean a huge failure to learn from history. And then maybe ten years later you'll be the one trying to warn someone else as they tell you how that time it's totally different.

Meanwhile, Mastodon dies. Lemmy and kbin might survive because they fill a different niche; however, if instances start federating with Threads and making it possible to follow people on there, then the same exodus will happen.

I agree that it’s a direct threat to Mastodon. I disagree same will happen to Lemmy and Kbin. I don’t see Threats ever becoming a anonymity oriented platform. It’s tied to an Instagram account.

Even if they support it in the future, just like Twitter and Mastodon, the primary users will be real identities. That goes directly against the concept of Lemmy and Kbin.

Not everything fits the same paradigm. We can keep parroting the history just for the sake of it or we can adapt and see that things evolve over time.