Whose fault is it though? If an instance is capable of 100 concurrent users but everyone flocks to the two or three big instances. What to do? Block instances so they shutdown? Then when the shit really hits the fan there's nowhere to distribute users to.

In the case of lemmy.world I might suggest they split the instance. Original lemmy.world keeps the communities but has no users. Create a new instance and transfer the users. That way the first instance is dedicated to federating the communities, moving the real time user database hits to a separate database. I'd also suggest preventing the creation of new communities on that instance.

In real terms it'd have been better if the communities were shared between instances more. Making a more even spread of the one to many distribution efforts.