In episode 8.04 (The Last of the Starks) of Games of Thrones, the story continues to march along with the characters continuing to prepare for the future by playing 'The Game of Thrones',
as none of them really discuss how this all happened and with the belief that the Night King and/or the threat of the White Walkers has been resolved.
But Bran mentions to Tyrion that he now spends most of his time in the past.
But if this was really the case,
that The Night King, The White Walkers, and by extension the Azor Ahai prophecy has been fulfilled or is now inconsequential,
then why is Bran spending so much time in the past NOW?
Besides this being a possible clue about those other things, is there any other logical reason why he would be doing this?
To Better Explain:
And while I'm well aware of the following exchange:
Bran Stark: Yes, he will. He'll come for me. He's tried many times before, with many three-eyed ravens.
Samwell Tarly: Why? What does he want?
Bran Stark: An endless night. He wants to erase this world, and I am its memory.
Samwell Tarly: That's what death is, isn't it? Forgetting, being forgotten. If we forget where we've been and what we've done, we're not men anymore, just animals. [to Bran] Your memories don't come from books. Your stories aren't just stories. If I wanted to erase the world of Men, I'd start with you.
It does not answer the specific purpose of any given 3ER, except to say that his existence threatened the Night King; it does not answer why a 3ER is needed to be the world's memory!
At the heart of my question, I'm looking for this answer, because as it stands, the bigger threat seemingly has been lifted and Bran's knowledge has been used sparingly (and potentially destructively) and there is little evidence to support why either Bran or any 3ER would need to dwell in the past or if this is just a natural byproduct of being a 3ER? Is this what they all do, or does Bran have a choice about what he chooses to look at, and when?
Is he looking for something specific for a specific purpose that relates to the story we have left or his dwellings moot?