Who cares? If shipments mean anything, why not just cut aluminum blocks into trillions of pieces and ship those? There's your volume right there.
Oh, wait, no one would buy just a little piece of aluminum. No one would develop for just a little piece of aluminum. No one would be satisfied with a little piece of aluminum.
Generally shipments do have some amount of correlation to sales. These shops aren't ordering more to sit on the inventory indefinitely. You should also note that Apple does report shipments to authorized resellers as sales, so it's a little more ambiguous than you might think. All of them are eventually sold. I'm not denying that. It's just that the debate on the numbers is getting old.