Nah, there is an actual tendency to make books longer for no good reason.
Lack of editors has been a common problem for decades, especially visible as authors get famous.
You usual target a wordcount for a market, as I understand it. You can't sell (to a publisher, I mean) a YA book that's 600 pages in a mass market paperback. You can't sell a 220 page hardcover to a publisher that wants big fat doorstop fantasy novels.
That only means publishers are accomplices.
They do that because they think it's what will sell. They might be wrong, but I'm pretty sure they have better insight into the market than I do.
There's short books that feel interminable and long books that fly by.
It's amazing that a professional writer would espouse the opinion in this article publicly.