Because worlds like Greyhawk and Forgotten Realms are chock full of history and other types of information.
Yes, but a lot f that history and "other types of information" has already been published...much of it multiple times.
I want a full hardcover book on Greyhawk, and a big fold-out high quality map. I want a description of each region, and adventure hooks throughout. I want details main characters and villains. I want suggested locations for classic dungeons. I want unique magic items famous in that setting, and perhaps some unique spells for it as well. I want to know more history, more politics, more detail maps of cities and towns. I want to know the general resources of places to deal with a crises that might arise. I want to know so much from that setting!
Sounds good. This fits into my idea of a "Classic Worlds" product.
Saying "why more" is to me like saying "Why put out Lord of the Rings and The Silmarillion once you already published The Hobbit? Just write something totally new!" It's pretty hard to get to that level where you can believe, for however a brief moment of fantasy, that such a world rings so true that it could exist out there somewhere. And you do that by developing it thick with consistent interesting details over hopefully multiple books.
I don't think this analogy works at all because the "LotR" and "Silmarillion" of Greyhawk already exists in that there is a ton of material out already. I think a more accurate analogy would be, after the Dragonlance Chronicles and Legends were published, asking "why more?" The More became an endless stream of novels and short stories, and then later books revisiting the characters from the original series...and the whole thing got over-saturated and, quite frankly, beaten to death.
We see this time and time again. Rather than a new science fiction franchise, we get a re-hashing of Star Trek, but this time for Gen Texters. A lot of the original vitality is lost - especially when you try to re-create things like the chemistry between Kirk, Spock, and Bones, or the classic villainy of Khan. I would have rather seem them start with an Enterprise after the Next Generation - with a clean(er) slate. The death of Kirk scene in the recent Star Trek movie ended up being almost comical in comparison to the epic drama of
Wrath of Khan.
Back to D&D. With the Forgotten Realms, there was the original treatment in the grey box and the 1e/2e FR series (IIRC, FR1 was one of the first 1e/2e crossover products, along with
Greyhawk Adventures). There was also a wealth of box sets for 2e. Then you have the great 3e hardcover book and a bunch of hardcover supplements detailing regions already covered by the FR series, but in a 3e format. Rather than doing that all over again for 4e, they opted to dial forward the chronology and change the Realms, which proved to be disastrous.
The point being, when you have a product line like Greyhawk or the Forgotten Realms and you come to a new edition, you have four options (that I can think of):
1) Discontinue it.
2) Re-invent the wheel with a new edition's version of supplements (e.g. 3e Forgotten Realms)
3) Re-make the setting (e.g. 4e Forgotten Realms)
4) Create a commemoration book or product, then move on
As I see it, with at least the classic settings like Greyhawk and Forgotten Realms, #1 is not an option - too many people love them and want to see
something. Jakandor? We'll never see another product again. Birthright? That's probably extinct as well. Mystara? I'd like to see a commemorative product, and wouldn't be surprised to see one, but it probably won't happen and probably doesn't need to happen. Dragonlance, Dark Sun, Planescape and Eberron? This is where we get to the settings that we'll probably see
something for - the more popular ones that are a bit too specific thematically to fully support, but have a strong enough following that some kind of 5e treatment is recommended, even if it is minimal.
But then we come to Greyhawk and the Forgotten Realms which, I imagine, are the two hallowed settings and will live on in some form or fashion for as long as D&D does. #1 is not an option. In the past, they've tried #2 and #3, which worked to varying degrees. But again? #3 was a terrible decision for the Forgotten Realms, although the
From the Ashes Greyhawk wasn't quite as drastic. I do have a feeling that both will be "dialed back" to their more classic iterations - Greenwood's Faerun and Gygax's Flanaess, although could be wrong.
But the problem here is that with #2, you're just by and large regurgitating old material and re-packaging it. Nice for one or two products, but a whole line? And for #3, you end up butchering something a lot of folks grew up with, and causing more harm than good.
I'm recommending #4. You still get to, if not please then
appease the diehard fans of the setting by offering a new and shiny version of their favorite setting, but you also get to explore new territory - create new worlds. Isn't that what its all about? Don't we want new worlds, new adventures? Sure, I'd love to run some classic modules in my upcoming 5e campaign, but I for one would much rather see a new world developed rather than
yet another round of the Forgotten Realms or Greyhawk, at least beyond the initial product that I do fully endorse.
Anyhow, in conclusion I'm not just talking about personal preferences for game settings, but touching upon the nature of art, creativity, and aesthetics - and the problem of (too much) derivation (especially with what I said about Dragonlance and Star Trek). If I'm to play Devil's Advocate to myself, I would argue that with RPGs the main thing is
fun and playability and, at least for the older generations of players in their 30s-50s, recapturing a sense of wonder we experienced in our youth. For that its hard to beat Greyhawk or the Forgotten Realms.
