This is a neckbeard dream, and it is why activity pub will never take off.
Grandma ain’t running her own instance, but she can swipe her card and get “grandmahotstuff.com” tied to her ATproto DID.
As long as the did is maintained by a neutral org like let’s encrypt, and icann remains functional, it’s a superior model, as those orgs are now tied to the functioning of the internet itself.
Nothing that involves authoritative state of data can be decentralized. Ultimately something is a source of truth. Who decides what the torrent data is? Congratulations, your system is now centralized.
Decentralized systems are anarchist mastubatory fantasy, distributed systems are what runs the world.