The problem with client P2P is there’s no aggregation at scale. You can’t even accurately calculate things like post likes. Not to speak of recommendations, search, and all other basic things people expect from social apps.

Atproto is an attempt to engage with the problem space in a way that hits the baseline UX of Web 2.0 apps.

But it’s worth noting atproto designers come partially from P2P lineage. Some worked on Scuttlebutt, IPFS, and others.