We might need to normalize having Nostr clients support export and import backup functionality — saving to local disk, iCloud, Google Drive, or wherever. Not everyone will run their own personal relay so this might be a good alternative.

Won't that take us back to centralized authority or is that a risk we are willing to take in the name of storage space?

Please choose services that are privacy friendly, and E2E. So no google drive, one drive. There is proton, pcloud, nextcloud... Icloud is also E2E now

nostr works because it is not p2p

When is that?

This is every Friday in Lisbon. But it's a "crypto" meetup, so expect shitcoinery. https://www.meetup.com/theblock/

And this is once a month in Lisbon, and Bitcoin only. https://www.meetup.com/lisbon-bitcoin-maximalists/