I might be mistaken, but from what I read the main addition is that all peers replicate the full state.
If you have a dominant xmpp server (like gmail was) that removes xmpp support, its users have the start using other clients to connect to it or start a new social structure from scratch. In essence this makes the xmpp server a dominant player with leverage.
If gmail had used matrix when it pulled the plug all interactions (who knows who, how to route traffic, chat history) would have been replicated at the peers so it would just have removed google’s servers from the equation. The people who had been using it would continue uninterrupted.
If you have a dominant xmpp server (like gmail was) that removes xmpp support, its users have the start using other clients to connect to it or start a new social structure from scratch. In essence this makes the xmpp server a dominant player with leverage.
If gmail had used matrix when it pulled the plug all interactions (who knows who, how to route traffic, chat history) would have been replicated at the peers so it would just have removed google’s servers from the equation. The people who had been using it would continue uninterrupted.