Re: What is the big deal?
No, not really—and that's a good point, Tom. Actually, Windows aggregate market share is up recently, and OS X is slightly down.
That said, there's some fuzziness in these numbers if you try to pinpoint things too specifically, since the stats theoretically represent the entire computing market, not just the most recent trends. Given how many Windows XP machines there are still in use, this vantage point is massively biased toward Windows. Windows used to have an even bigger share of the market, so the residual effect of that advantage diminishes our ability to perceive gains Apple makes in the short term.
I mentioned that Windows share is up recently. If we extend back a bit further, OS X starts to gain, and Microsoft to lose. Why the shift over recent months? Simple—though some Windows XP users haven't upgraded, millions did, and most of them went to Windows 7. During the same period, Apple offered just about the most incremental updates imaginable, nothing too inspiring.That sounds like a recipe for a temporary shift in purchase trends that doesn't necessarily say anything about the next 12 months, especially in the high-margin markets.
Apple's strategy at the moment is to make existing machines slightly better and slightly cheaper, which I see as a way to gain a few new customers until Broadwell-class Macs compel upgrades next year (e.g. the rumored fanless 12-inch Retina MacBook and 4K iMac). Anyway, I still think the numbers suggest Apple is eating away at Microsoft over the long run, even if Windows still maintains a gigantic lead, and has recently ticked up a bit.
Comparing the profitability of OS X (which is tied to Apple's hardware margins) to the profitability of Windows (which is tied to a million things) isn't an apples-to-apples comparison, either.
It's also important to remember that Microsoft has been forced to essentially make most versions of Windows free to OEMs, which doesn't suggest Microsoft's desktop market share is some unassailable force. I expect more of this diminution of Windows as a direct revenue source will follow, though perhaps Nadella has some ways to create new cash streams, such as the rumored, and hard to imagine, Windows as a Service offering. Anyway, Microsoft's willingness to give away Windows says a lot about developer loyalty, OEM interest in Android and Chrome, as well as Apple.
All that said, Windows remains a very strong brand, Windows 8 notwithstanding. I expect it to continue to be the desktop UI used by the majority of users, even if OS X continues to become more popular. But Windows can still lose a lot of battles while maintaining market share. It's one thing to try to defend your turf, and another thing to keep expanding your territory.