The point isn’t to rewrite history. It’s to give users a safe, forward moving identity. A client uses the lineage event to know which key represents the user now. Readers see the active key (A'), new posts come from A', and old posts stay where they were signed under A. Nothing needs to be merged or remapped for the UX to make sense. This is the same model used everywhere else: PGP subkeys, SSH key rotation, Bitcoin wallets. Identity advances, history remains immutable. Rotation becomes survivable, and the user keeps continuity without any protocol changes or heavy client logic. That’s the entire purpose.