A lot of it isn't new, but this quote did jump out at me. "Other factors we consider are things like ‘Do we have an idea to sufficiently differentiate this experience from the other worlds?’"
See that? That's why every setting book they put out has a hook or gimmick to make it unique, and that's why there's no Greyhawk book on the release list.
Yeah, people have been pointing that out for a while now. Ravnica was their giant magical city and faction war setting while also serving as their first M:tG setting book. Theros was their Greek mythology setting with M:tG-isms plugged into it. Ravenloft was their horror setting, Eberron was their magitek dungeonpunk Cold-War setting, Strixhaven was their magic academy setting, and Spelljammer is their space opera setting. Dragonlance is their nostalgia setting that also doubles as testing out some mass combat warfare rules to incorporate in a 5e minigame.
The only reason Greyhawk would come to 5e is to capitalize off of nostalgia. We already have enough generic fantasy settings in D&D 5e (Exandria, Dragonlance, Forgotten Realms), so it really wouldn't have any role to fill other than "this is Gary Gygax's setting, a lot of older players want it back, and the 50th anniversary of D&D would be a good time to make money off of it".
I hope that this points to the two completely new settings that they're working on being published and being very different from what we already have in 5e. I would love a modern or futuristic fantasy setting, or a prehistoric Dawn War/First World setting, or settings inspired by real world cultures/regions D&D hasn't done well in the past (Mesoamerican, Indian, etc), or something else that we've never seen in D&D or M:tG before.