I think the guy from Surly is in a far better position to say than most STW’ers.
But I would think context is needed, in terms of growing or expanding sales the bubble may have burst, plus size wheel’s offer a lot of choices in competition with fatbikes. But I doubt the bubble has burst for those owning and enjoying riding their fatbikes! And I’m sure more will be sold, and for some it might always be the right bike.
I guess, I wouldn’t be looking to set up a company solely selling fatbikes in light of the comments if I wanted to make my millions. But to be fair, if a tyre gets wider than 25mm, I’m out 🙂