Immortality and the sons of Elrond

[Inziladun]

Originally Posted by Tuor in Gondolin

But couldn't that quote be taken to mean, "I haven't
gotten around to writing it, or maybe I'll keep it
untold to add to that sense of depth I like"

Of course it could. But to me that means any speculation of the fate of the two is just that: speculation. If they chose the life of the Eldar their options were limited to remaining for a while in ME and then sailing into the West, if they could find or build a ship to bear them, or staying indefinitely, until they, in the words of Galadriel, "forget and (are) forgotten". If they chose mortality, they probably had at least a couple hundred years ahead of them, comparable to Arwen, but I would again question whether they were in a position to do anything really meaningful in the Fourth Age.