if you can understand the need to be conservative with errata, then one should be able to understand the need to be conservative with lore changes. The reasons are similar.
Not as I have encountered the game for going on 35 years.
The mechanics of the game are generally taken as a baseline - houserules are just that, namely, local departures from a shared baseline. Errata can cause confusion over what the baseline is.
But the lore of any particular setting has
never been taken as a baseline. I remember when UA came out in the mid-80s, and there were complaints in Dragon magazine that it seemed to be treating the World of Greyhawk as a baseline (with Valley Elves, the rules for the Barbarian class, etc) and this was understood as contrary to the basic tenor of RPGing - where the default, as far as setting is concerned, is that tables make their own choices.
You are
literally the first person I have ever encountered who actively has as a goal for RPG play to emulate someone else's fictional idea by means of your play, such that if it turns out someone else interprets the source material (say, DL) differently, you get upset. (For clarity: what you are saying you want to do is very different from the person who sets out to play a PC who emulates his/her own conception of Aragorn, Conan or whomever. For that person, it doesn't matter if someone else interprets the source material differently.)
running a homebrew game isn't incompatible with a conservative idea of lore.
Of one's own lore. Not of others'.
Using the lore doesn't mean holding it in stasis. It means using it in play, to inform characters and narratives and mechanics. It necessarily changes and develops in the course of play. But if it changes because some developer had a Cool Idea, that disrupts the characters and narratives and mechanics that were part of that lore before.
<snip>
changing game lore automatically disrupts existing games using old lore just as much as a errata does.
What is the mechanism of disruption?
All you're pointing to is that people feel
invalidated because another author, whose work they were emulating, changed what s/he thinks about the work in question.
But why do people feel invalidated? If you are happy playing your game using supplement 101, and then supplement 102 is published which contradicts supplement 102,
why dose that disrupt your reliance upon 101? How are you worse off than if 102 had just never been published?
if you build a character to be a powerful two-handed weapon user, and you use the game's mechanics to realize that goal, and then a new book comes along and nerfs a key part of your build, that disrupts your play. Even though RPG mechanics are meant for player input, even though you can use the old rule just fine, that change has a negative effect on the game you're playing.
This isn't true. (Perhaps it accurately describes how these things affect you. But it doesn't generalise.)
In my 4e game, there was a player playing a character who used CaGI as a key part of a polearm martial controller build. WotC released errata that (in my view, and the player's view) wrecked CaGI in an attempt to appease the "dissociated mechanics" crowd. But that errata didn't disrupt anyone's play at our table, or have any sort of negative effect, because . . . *drum roll* . . . *wait for it* . . . we ignored it!
Conversely - it seemed obvious to me that Weapon Focus was meant to be a buff for martial characters, not spell-using ones - so a player shouldn't be able to take the Weapon Focus feat for his/her PC and get a buff to both Weapon and Implement attacks. So we implemented that rule. When, a year or something later, WotC released errata to the same effect, it didn't disrupt our game because we'd already noticed and solved the problem!
The same thing is true if you build a society of gnolls with active trade with your central kingdom, using the game's lore to realize that goal, and then a new book comes along and claims that gnolls are all destructive demon-spawn. That disrupts your play in basically the same way.
No.
In my 4e campaign it was clear from the start that the Raven Queen was something of a grim god. Subsequent published material gave a different impression (eg the E1 module). That didn't disrupt any play at my table - we just ignored it!
The idea of "outsiders" [? souls that don't get to go to heaven] and islands around the Astral Domains, that was published in The Plane Above, doesn't do anything for me and doesn't really fit with the ideas about the afterlife that have emerged in our game (which instead revolve around
The Bridge That May Be Traversed But Once - see also
here). But that's OK, because I just ignore all that stuff, and my players certainly don't care about it.
It's more meaningful because you've used the canon to have an impact in play.
Why does the impact of some story idea upon the play, by you and your friends, of your RPG campaign, depend upon
validation by a commercial publisher who (in your case) is on the other side of the country and (in my case) is on the other side of the world?
That makes no sense. At least, it makes no sense to me. I don't play my game to please WotC by faithfully adhering to the stuff they think is worth publishing. I play my game to please me and my friends.
Another
Ryan Dancey quote seems apposite here:
We can demonstrate a commitment to supporting >your< stories. >Your< worlds. And we can make the game fun again.
Our customers were telling us that we produced too many products, and that the stuff we produced was of inferior quality? We can fix that. We can cut back on the number of products we release, and work hard to make sure that each and every book we publish is useful, interesting, and of high quality.
Our customers were telling us that we spent too much time on our own worlds, and not enough time on theirs? Ok - we can fix that. We can re-orient the business towards tools, towards examples, towards universal systems and rules that aren't dependent on owning a thousand dollars of unnecessary materials first.
I play the game to tell
my group's stories. Not TSR's or WotC's. The material they publish is just a means to that end.
I don't care if someone changes canon, but what can ruffle my feathers is what changes are made.
