Could it be that the decline in sales for the story picture books is what the editors are alluding to? The pure picture book will be less wordy, with a decisive advantage to those who illustrate as well as write.
They really are two different kinds of picture books, and the illustrated stories are out of fashion. Not with kids, (if you have kids, you’d agree) but with their parents who read (and are asked to re-read) to them. Editors must respond to the market.
Seeing some of the classics mentioned above ^, I can’t help but hope for a HP-like phenomenon for the world of picture book publishing. Before Harry Potter burst on the scene, editors insisted on shorter books, and many would not look at fantasy. After HP, writers feel they have to apologize for a middle grade that is below twenty thousand words. Now imagine a spectacular selling new story picture book that has 1,200 words. Commercial houses doors will fling open.
I’ve written both kinds of PBs. My comments are not about mine, but about the market observations here.