Because it doesn't matter. I don't understand why people have the need to update the setting. It's not Eberron or Dark Sun where you need new rules that are 5e-specific.
More bluntly, the things that remain special about Greyhawk as a setting are the things most likely to get screwed up if they get touched again. In other words, Greyhawk isn't FR, and I'd rather it just be mentioned in passing than have it turned into that.
But that's just my opinion, and I created the poll and the thread to see what other people thought. Because I am not the KING OF EVERYONE! .... yet.
I do agree about that, but the problem with just saying “the old stuff is good enough” is that it’s not readily available. Yes, it’s on eBay, and digital copies from Drive Thru RPG, but that’s different. Not to mention many people won’t get it if it’s not 5e.
There are some rules in most of the books, but a repackaging of a “legacy” setting might be an interesting approach. Although even with Greyhawk, which do you pick? And many would complain that it’s just a reprint.
Another factor, that you touched on, is that Greyhawk is the ultimate DIY setting. I agree, especially in the early years, but the entire framework and support of the game was set up for that sort of thing. The adventures notated locations in Greyhawk, but rarely had a close tie to it that altered the lore for the setting. Dragon magazine basically promoted the approach of making the game your own, since the bulk of it was deemed “unofficial” and there were all sorts of homebrew variations for rules, lore, classes, monsters, etc.
While there is some of that discussion, in the DMG along with the promotion of things on DMsGuild in Dragon+, it’s different than when full articles appeared instead of just saying, “this is good,” and when the DM designed campaign/world was the default. On the one hand, it’s a golden age of homebrew now, but on the other hand there’s almost too much. And while the quality wasn’t always great in Dragon, at least it was chosen, edited, and presented in a consistent and digestible way. The current approach is more of a product review.
So I don’t necessarily disagree, but there seems to be a consistent group complaining that everything is in the FR and they need to release other settings too. I really dislike the way they’ve homogenized the settings over the years, although part of that is how they also dump everything into the Realms. I fully expect it to happen if they release a Greyhawk setting in any capacity, but Ill be even more disappointed if they dump Dragonborn and tieflings, among other things, into Greyhawk.