A lot of organizations completed upgrading to win 7 (mostly from XP but some from Vista) two or three years ago. From a business perspective, i don't see why they would want to upgrade now given that win 7 does what they want and is pretty stable/efficient. This also applies to regular people who get their job done on win 7 and don't want to go through the hassle of upgrading. You could argue, that win 8 is not sexy enough that it would push people to upgrade, but I would say it's a timing issue combined with how win 7 is still going solid, so I won't necessary blame Windows 8 for the low numbers.
