One thing Apple has done really well over the past few years is eliminating fragmentation in its operating systems. The install base of iOS 5 is over 75%; OS X Lion is around 50%. That’s in less than a year for both operating systems.
To put those numbers in perspective, consider this. Google’s latest operating system, Ice Cream Sandwich, still runs on just 1% of all Android devices after a year, and Microsoft’s Windows 7 operating system hovers at around 50% after almost three years.
Apple’s secret is simple. They charge as little as possible for their operating systems, giving it away free if they can. It’s a good strategy that prevents Apple from having to endlessly support older OSes. And now, Microsoft’s finally going to take a page from Apple’s book.