But, that’s not relevant to communities. You can kill a community by technical means, but technical means cannot create one; it’s necessary but not sufficient, and not even the hard part.
Most people are still on fucking FACEBOOK. They are willing to put up with almost unlimited bullshittery for the sake of their sense of community. Building a better mousetrap won’t work, and building a vaguely equivalent mousetrap won’t even move the needle.
They are all available on every instance. It’s not different than having five communities for the same subject on Reddit. It’s worse here right now because so few communities have managed to “clear their orbit” yet, but it will get better.