I'm the Fag who is dumping his setting, and this point is part of why I made my own setting to begin with.
I am not and will never be an authority on the forgotten realms, or Eberron, or any other setting. I made my own so I was the authority, I know it all because I wrote it all. I started with a mostly blank continent, drew some lines, then asked my players what they wanted to be. I then added elements that would allow them to be that. And I told them what they would know being from this place or that and anything they don't know, I can tell them as they learn it. This way they don't have to fumble in the dark or have to be given a rundown of a certain place because they know, their character knows. And I have an answer that I won't have to flip through the book to find.
I made it for fun, not to be original. And as I add things, I expand on it, and what actions my players take can change the world as they have adventures in it.