Everyone doesn't need to run a relay, but everyone could. Running a relay is already incredibly easy to do, and costs nothing, and that'll just get better. It's not decentralized, if you need to traverse "approved" hubs to get from point A to point B. That's not only a protocol question, that's an implementation question. We are emphasizing a complex, sprawling network of privately-run nodes, preferably communicating offline or over Tor, to avoid the centralized fate of email. Every relay operator is free to let me use his relay or not. This is a nonviolent protocol. We do not need consensus in event content or originators. We just need lots and lots of different paths, and to ensure that anyone can build their own path.