Good animation show is likely to be much more successful and less expensive to break even. A crap TV show is likely to generate nothing but bad press and pass mostly unnoticed
There is market for animation, even if it's smaller than live actions. Arcane made far more buzz than The Wheel of time.
It's not like Cosmere had such a high marketability potential anyways. A live action seems like just a huge waste of money
The thing is, if you make animation show, chances are you're never going to get to mainstream market - and that's what most streamers are trying to do with "the next GoT". True, if you're fine with fantasy being niche (I am, it is better that it stays that way after what they're doing to it lately, and Wheel of Time is a perfect example), then animation is more than obvious choice.
There is no next GOT, mainly because GOT isn't big because of the fantasy side, but because on its heart ASOIAF is a book about political conflicts, it's much closer to series like The Tudors than most fantasies. If they pursue a next GOT, Stormlight might be one of the worst options in the market
Fantasies seems to have more market space when they are juvenile, like Harry Potter, Narnia or Dark Materials.
That's said, it's hard to regard Stormlight as t even Fantasy, is something more akin to sci-fi really (and Sanderson plan is to make late cosmere book to be sci-fi based). Things are just too... strange, to resemble fantasy. The species are made-up, there are planets and travel between them. Rythmn of War have large sections explaining a lot about lights, mater and anti-mater, energy, engineering. The magic seems to be really grounded by physics. In Mistborn era 2 they are in XIX levels of scientific progress and this looks a lot like a The Legend of Korra
I truly believe Cosmere is a Steampunk universe disguised as High Fantasy