This is a shame. Hosting a high visibility server is no joke, and I don't envy the admins and the very difficult work they do. It's simultaneously an argument for and against decentralization. For - a single instance can get knocked out without talking out the whole fediverse. Against - it seems as though high visibility communities are potentially fairly easy to target and take down.
I think that decentralization wins out here in the end, but it does feel like there may be a need for some sort of fallback mechanism to be in place at an instance/community level. I suspect this might evolve somehow over time. It would require some way to expand trust between instances and or portability of communities (which could be fraught with user trust/data integrity issues).
If things don't evolve it could grow into a whack-a-mole game for bad actors, or there might need to be more investment into server infrastructure (which could work against decentralization if only because of economies of scale).
Or maybe there's no issue after all? I'm just imagining potential implications of a scaling fediverse - it's fascinating and exciting stuff!
Thoughts?