Seems reasonable. I'm partial to the Cosmere RPG, so I am trying to temper my read on the situation. But the evidence, such as this survey and the Amazon monthly sales numbers, do seem to indicate it is selling very well indeed.
Out of curiosity, the Call of Cthulu Core books are each at 100+ in the past month, Daggerheart Core does not have a number, Pathfinder 2E Player Core is at 50+, and the Stormlight Archive Starter Set is at 200+.
Well, given that the DMG has a fairly full (as in, about as much detail and info as the original Folio) presentation of Greyhawk as a Setting to run Campaigns, thing is newer players in the past two years have been primed to be open to borrowed Greyhawk nostalgia by WotC.
I mean, granted as far as it goes, I don't see any of that as a reason to not suspect this could be for Season of Champions. I would expect either a full veto of this material or adoption close to as is, not much back and forth.
As someone who finds the results intriguing, if not even promising, I do think it worth taking then with some grain of salt as partial and somewhat obscure. But I would have said the same thing about ICv2 at any point, while taking it seriously as a source of some information.
My main caveat...
Yeah, honestly I have doubts that "being a Lich" will make it through UA: if they wanted to explore the mechanical approach, really think they ought to have started with a less extreme narrative example.