There's probably a number of reasons why this might have happened (and we're sure you can come up with more than we can), but nevertheless, here you go: overall Mac sales are up by 21 percent in October and November since last year at the same time, according to Gene Munster (not pictured), analyst at Piper Jaffray. Desktop Mac sales are especially huge, with the rise as high as 74%, which seems like a typo next to MacBook and MacBook Pro increases of just five percent. In fact, those gigantic desktop sales, some reason, might actually be the reason behind the recent iMac delays.
At any rate, no matter why, Apple is making a boatload on Macs this quarter already. Even without the bulk of the holiday season, the desktops were already flying off the shelves in huge numbers compared to last year.
AppleiMac 27-inch with Retina 5K display (late 2014)