It isn't at all clear yet that their open cycle engine is dated. Raptor has yet to prove reliable. Perhaps it will be, perhaps it will not. It is fundamentally

It isn't at all clear yet that their open cycle engine is dated. Raptor has yet to prove reliable. Perhaps it will be, perhaps it will not. It is fundamentally harder to start the full flow staged combustion cycle, so time will tell if they can make this work as reliably as they have the merlin. SpaceX still makes all of their money with a simple open cycle rocket engine, and it burns RP1 which is expensive to clean up. Prometheus would be better in that regard.