p2p is obviously ideal but fails in practice due to the nodes being offline problem and notes not loading. nostr is a really good store-and-forward network though with efficient set reconciliation (negentropy), so it has a lot of opportunities to take advantage of p2p. Just seems unlikely p2p will replace relays entirely due to its unreliability.

Outbox model is already tricky, p2p would be techniques that extend outbox to online peers. most likely for DM purposes though, not really microblogging content where many people are consuming at once. It may seem simple to just say “just switch to p2p and everything will be better”. But i don’t think it would actually work for microblogging 

 Nostr currently works great for confidently blasting out an ill informed opinion about how nostr fails if you don't listen to me. 

Maybe be the change you want to see in the world and 1 popular client making it's users relays as well would be an improvement. If you're right, everyone that doesn't use your client fails.