Unlike web scraping where spaghetti logic is required to follow abstracted JS links, archival of nostr events can be as simple as running a relay and mirroring blog content.[1][2] nostr does a lot of what NNTP did but with additional flexibility.

[1] https://logperiodic.com/rbsr.html#nostr

[2] https://github.com/hoytech/strfry/blob/master/docs/negentrop...

For that you will need to connect to all relays in existence, right?

Users currently tend to push events to massive relays but decentralization is still a goal:

https://raw.githack.com/dtonon/oracolo/master/examples/fiatj...

https://github.com/nostr-protocol/nips/blob/master/65.md

Still, the short answer to your question would be "yes."

Not necessarily, the gossip/outbox model (NIP-65) tells clients which relays they should check:

https://mikedilger.com/gossip-model/

It is of course possible to combine this approach with undifferentiated access to well known relays, to fetch content from not followed people.

You should take it upon yourself to save your data, if it is really important to you, so that if all your relays fail, you can simply rebroadcast all your events to a new one and you will be fine. It's a problem solved in a collaborative and decentralized way.

> You should take it upon yourself

> It's a problem solved

If I have to take it upon myself, then it's not solved.