It's just hard to square with D&D's design, which has always assumed that magic is commonplace. The Monster Manual alone requires magic to be plentiful.
You can make a low magic setting, and people do. With significant effort. I don't see how that would work for the sample setting in the DMG. Greyhawk 2024 has to accommodate the main design principles of the game, including all of the species, creatures, magic items, etc. of the 2024 books.
I'm assuming they will leave things like demographics relatively vague, so that DMs can make whatever assumptions best fit with their vision of the game. But you just have to look at the covers of the new books to see that this is not being pitched as a low magic fantasy experience, and Greyhawk will be part of those books.