Some of Windows 7's gains certainly came at the expense of Windows XP, which has fallen more than 11 percentage points, a 28% decline, since October 2012 as users abandoned the old OS.
By making Windows 7 available, Microsoft and its OEMs not only continue to serve customers who want the OS, but make sure that new PC sales do not slump even more dramatically than they have already.
Consumer PC sales have plummeted — last month Microsoft said sales of consumer-grade Windows licenses fell 20% in the December quarter compared to the same period the year before — while the Redmond, Wash. company's business line of operating systems grew 12% year-over-year. In effect, enterprise spending kept PC shipments from tanking even more than the 10% contraction the industry experienced in 2013.
Extending Windows 7 Professional's availability on new hardware will also give Microsoft breathing room to continue its retreat from Windows 8's radical shift to a touch-first, tile-based UI, and to roll out a successor that caters even more to customers who rely on keyboard and mouse.
Microsoft is expected to unveil an update to Windows 8.1 this spring, perhaps in April, that will restore several desktop-oriented features and tools. Some reports based on leaked builds of this Windows 8.1 Update 1 have noted that on non-touch devices, the boot-to-desktop option will be enabled by default; if accurate, most users of traditional PCs will skip the colorful, tile-style Start screen. Windows 9 may appear as early as April 2015.
Retail sales of Windows 7 by Microsoft to distributors and customers were officially halted as of Oct. 31, 2013, but that deadline has been meaningless, as online retailers have continued to sell packaged copies, sometimes for years, by restocking through distributors who squirreled away older editions.
As of Saturday, for example, Amazon.com had a plentiful supply of various versions of Windows 7 available, as did technology specialist Newegg.com. The former also listed copies of Windows Vista and even Windows XP for sale through partners.
Even after Microsoft pulls the plug on Windows 7, there will be ways to circumvent the shut-down. Windows 8.1 Pro, the more expensive of the two public editions, includes "downgrade" rights that allow PC owners to legally install an older OS. OEMs and system builders can also use downgrade rights to sell a Windows 8.1 Pro-licensed system, but factory-downgrade it to Windows 7 Professional before it ships.
And enterprises with volume license agreements will never be at risk of losing access to Windows 7, as they are granted downgrade rights as part of those agreements, and so will be able to purchase, say, Windows 8.1 or Windows 9 PCs in 2015 or 2016, then re-image the machines with Windows 7.
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