Another thread, another argument. In effect, the following statement was made:
This, of course, could not stand, and various and sundry opposing armies (consisting, no doubt, of Dragonborn) were mustered to fight over that contention. The following two pieces of evidence were those most clearly adduced:
From Mike Mearls in an interview prior to the release of 5e:
From Jeremy Crawford in a series of tweets in January, 2015:
This has led people to argue that, inter alia, Mearls has said one thing (FR is the setting) and Crawford is saying another thing (it is not).
I disagree. I think that there is a meaningful difference between the following two statements:
1. Forgotten Realms is the default setting in 5e.
True.
2, Forgotten Realms is the official setting in 5e.
False.
I think that this is the point that Mearls was making and that Crawford was trying to make clear (or less clear, depending on how you look at it). 5e does not have a single, unified, official setting. Nor should it. The majority of campaigns that are run are some variety of homebrew, so it would be somewhat foolish to demand an official setting. In addition, one of the core strengths of D&D is the multiplicity of worlds that exist and have been created (or, to put it more crassly, the IP that D&D has developed over the years).
That is why the core books reference multiple worlds and campaigns. See, e.g., the PHB section on the different gods, and the multiple planes and campaign settings. The core books do a wonderful job of introducing the concept of the multiverse. The DMG begins by discussing the multiverse! I would note, however, that many of the samples in the DMG come from ... the FR. Harpers, the Calendar, Evernight, etc.
However, it is also obvious at this point that Forgotten Realms is the default setting of 5e. From the first introduction that many players and DMs receive in Phandelver, you see a FR-centric emphasis. Looking at the APs, you quickly see that every ... single ... AP is published with FR in mind. To publish a module that doesn't have FR in mind (like the two, arguably, that don't ... Saltmarsh and Strahd) is a noteworthy event. Even when collected modules, many of which come from other settings, are published (Yawning Portal) a hook is inserted to make it FR-centric.
Names of expansion books (such as Volo's or Xanathar's) abound with FR-centric tropes. The one that doesn't (MToF) has nothing really that ties it to the campaign setting, and is explicitly about the outer planes.
Famously, DM's Guild only allows for material from accepted sources, including generic D&D and specific campaign settings- which are the campaign settings that have been published and stated with (of course) FR (although expanded to RL, EB, and Ravnica).
And the famous and long-rumored movie, when it comes out, will be set in the FR.
Which goes back to the original issue; FR is the default setting of 5e. Any given material, and given AP, is most likely going to be set in FR, with loose rules for translating it to other settings and/or your home campaign. It is not, however, the official setting.
At least, that's how it seems to me. I've included a poll (because FUN) and y'all can have at it in this thread.