The Gift of Speech

[the phantom]

if only Elrond remains even at RIvendell who knows all the old lore correctly

where do you find this? Glorfindel doesn't count? And with all the travel Arwen does between Rivendell and Lorien, wouldn't she get the stories straight? Her grandmother knew them all, I'm sure.

Glor, Arwen, and Galadriel knew everything Elrond did?

Wrong.

There were most definitely things that only Elrond knew or remembered accurately. From FOTR, The Council of Elrond-

Then all listened while Elrond in his clear voice spoke of Sauron and the Rings of Power, and their forging in the Second Age of the world long ago. A part of this tale was known to some there, but the full tale to none...

Glorfindel and Erestor were present and they didn't know. Hey, even Gandalf was there and he didn't know the full tale.

Then there's this from FOTR, A Knife In the Dark-

'I will tell you the tale of Tinuviel,' said Strider, 'in brief- for it is a long tale of which the end is not known; and there are none now, except Elrond, that remember it aright as it was told of old.'

And also, from appendix A-

When the kingdom ended the Dunedain passed into the shadows and became a secret and wandering people, and their deeds and labours were seldom sung or recorded. Little now is remembered of them since Elrond departed.