Not every user will be equipped to build, maintain or even run their own client/relay safely. These users will require either third party clients/relays as a service, or third party software they are not equipped to manage on their own. That does not translate in a true p2p network. there is still a chance fewer such trustworthy projects will support most users. Where are they hosted? who maintains them? true p2p is not feasible. there must be something in between. on the other hand #nostr already allows for p2p networking when honest alternatives aren't available. p2p alone cannot scale.
P2P can scale. Bittorrent. Massive. Put the grunt work on the clients, let the relays/nodes just route and transfer the data.
torrent is not used by a broader audience or in any similar way to how social apps work. there might be some use cases for p2p client/relay architecture, but it won't cover all that #nostr can be used for.
Why can't torrents be used for social media ? We need intelligent clients using vast amounts of data moved around the network. The former is not the problem and torrents alread achieve the latter. Torrents also achieve storage redundancy giving resilience and state.
it's not about technological capabilities, it's about the technical skill required to maintain such a system on premise. most people do not have that skill. even torrent has evolved to use third party hosted services, think popcorn time, stramio. only by doing that they are able to reach broader audience