Whether or not there is some bit of unreliability isn't really the point.
It's very much the point to
me! It recalibrates the lens through which we are invited to view the setting. The omniscient text of the game author is giving me "facts"; the voice of the in-world narrator is giving me a specific POV, one which encourages me to participate in the subcreation and weigh in with my own judgments. Which method, or combination of methods, the designer chooses to use tells you a great deal about how you're intended to interpret the information you get (or whether, indeed, there's meant to be an element of
interpretation at all).
When you look at games, lore is lore.
I ... buh ... I don't even know what that
means, man. I'm forced to conclude that the weight and value you attach to the word
lore is intended to loan this tautology some gravitas that is non-intuitive to me.
To me (
si componere magnis parva mihi fas est), it's as circular and empty of meaning as if you were to look at the works of Shakespeare and say "the text is the text," ignoring that the Henriad and the sonnets are utterly different genres and making no distinction between the quarto and folio versions of the plays.
It's treated as the way things are unless the DM chooses for it not to be.
Well ...
yeah. To quote one of my favorite unreliable narrators, I think I have been telling you nothing else for the last hour.
But there's a, shall we say, qualitative difference between "The baseline assumption is that
everything presented here is factual" and "It should be clear that you can't take everything this guy says for granted, but which is true and which isn't is up to you."
Even the Realms with Elminster is the same way. Greenwood created Elminster to be a spin artist, but didn't say what was spin and what wasn't. The DM deciding which lore was wrong and changing it is no different with Elminster than it is with lore that is simply written down with no narrator at all. In both cases the DM is taking a bit of established lore and changing it. He just has a more convenient excuse for it with the lore presented by Elminster.
Okay, but so what?
I mean, what is that assertion meant to imply about the greater worth and validity and authenticity of taking a strong canon-prescriptive stance on game settings? I feel a bit like you're flailing around here trying to be right about something while I no longer have a clear view of the point you want to make.
That said, would I be right in thinking you're hanging a great deal of weight on the word
established there? Because I feel like a great deal of what I and others who don't take a strong-canon stance here have been saying is that "established" won't bear up to what you're asking of it. There's no
there there. It's not quite, but nearly, unreliable Elminsters all the way down.