The moment relevant aspects of the game get locked behind some kind of 'you must be member of ... to be able to do this' it'll be the day I logout the last time.
Additionally, I think that it should be about removing the causes for the world going stale in the first place, not trying to cure the symptoms through mechanics that are only relevant once and, even when being able to postpone the inevitable for a short while, are completely meaningless afterwards - or even contraproductive like this suggestion, that would effectively speed up latecomers so they can burn through what content there is even quicker.