I feel there is some confusion about NIP-29, relay based groups.
Yes, they are centralized, obviously, they run on a central server...the relay it happens to use. Doing things like groups in this manner makes it subsequently straightforward, fast, not-buggy, and scalable.
You are still free to use whatever relay for such a group, including your own; and as a user you are still able to use whatever app to interface with the various groups running on various relays that you are part of (have a look at Nostrord (npub1ktx…zc2h) or https://flotilla.social/ or whatever you fancy) .
The point is the usecase and its context. You should use these relay based groups for (semi-)closed, moderated environments with a hierarchie that is in charge in context of a particular thing. The whole point is that it is a coherent environment, the whole point is that someone is in charge of "censorship"; its a house, you are a guest, and the fact that you can be yeeted out is a feature, not a bug. In this context, censorship resistance does not make sense, therefor decentralization does not make sense.
For example, we are running a relay based group for Kubo.watch (npub1kds…nsze) for user feedback on the app, and even integrated it nicely into the app itself (as should basically every client, to the extend they can be bothered to moderate an environment). As long as Kubo is a thing, that relay group will be a thing, because we have an interest in keeping all of that up and running. If/When Kubo is no longer a thing, whats the point of the associated group anyway?
On top of this, forking and migrating a group to another relay is possible. It might not be the cleanest proces in the world, but it does mitigate the risks of host-relay-failures.
Lastly, all of this exists within the broader Nostr context, you are not solely dependent on the relay-group to be and to stay into contact with others in that group, all the other means Nostr provides are still available to you for that purpose.
Its just another tool in our toolbox that we can leverage, and in this case constitutes an improvement over things like Discord.
Nostr.
