I've just read the article. I don't agree Andy wouldn't have been motivated by the WTF especially as he loves playing in front of a home crowd and also it's always a big energetic crowd. And it is a prestigious event. However, it's a bit irrelevant now any way. I was left wondering what exactly the point and purpose of the article was. I also felt it was written before Andy announced his back op - the reference to it seemed to have been inserted as a kind of necessary afterthought.
Probably just mindless filler, dressed up as expert opinion piece. It's the scourge of modern "journalism", and in this day of digital content, the quality control isn't what it was.
I suspect you are right and the piece was written before the announcement of Andy's surgery, and they decided to run it anyway, with just a minor tweak. It's a classic example of not letting the facts get in the way of the story.
I don't mind it when the pundits say they expected Andy to have a lull, because lulls after winning a slam, especially in those circumstances, are normal. However, they are definitely making way too much of it, especially in light of what everyone now knows, which is that Andy was playing through the pain with a back problem, very probably knowing that he'd be having the surgery, so no chance of a high year end rank etc.