I think the small set of public relays are fun right now but it is a luxury of a relatively small community. The spam will get bad (already started to see this yesterday) so public relays are going to get noisy and clients are going to need techniques to fight the spam.

One idea is just a way to send some sats to the relays you are connected to. This could whitelist your key for some amount of time, or PoW queries for strangers.

Maybe smaller private communities will take off, not many people doing that yet.

Lots of techniques we have yet to explore