Second, the backlash to Microsoft nullifying an upgrade path would be swift and probably fierce; there has long been a contingent of Windows users who see conspiracy in every upgrade, believing that Microsoft is "forcing" them to spend more money.
(It doesn't help Microsoft that on occasion it seems to do just that, as the recent Office 2010 Starter update snafu showed.)
Admittedly, there is no rule that says Microsoft must offer an upgrade path for an aged operating system until its support lifecycle ends. But Windows XP is not just any edition: Not only is it the longest-supported of any Microsoft operating system, but it's also the one with the largest user base this close to retirement.
According to Web metrics company Net Applications, XP powered 33.7 percent of all personal computers worldwide in August, or 37 percent of all systems running Windows. Rival StatCounter, which is the measurement firm that Turner cited last week when he claimed XP had a 21 percent share and would be down to 13 percent by next April, figured the old OS powered 20.6 percent of the world's personal computers.
While the extension of Windows 7 sales to retailers may be construed by some as another proof of Windows 8's lackluster uptake, that's probably more palatable to Microsoft than the furor it would raise by yanking Windows 7, at least officially, from shelves.
"Officially" is the key word, as Microsoft's sales lifecycle rules notwithstanding, Windows 7 will remain available at online outlets long after the Redmond, Wash. company's deadline. That's because retailers stock up on an OS before they're cut off from the supply. Amazon.com, for example, continues to fulfill orders -- through third-party vendor partners -- for Windows Vista, which officially met its retail end in Oct. 2010, and even Windows XP, which was supposed to disappear from retail in 2008.
Microsoft, in fact, posts a caveat of its own on its sales lifecycle website: "When the retail software product reaches its end of sales date, it can still be purchased through OEMs (the company that made your PC) until it reaches the end of sales date for PCs with Windows preinstalled," Microsoft states.
Diehard XP users in larger businesses won't have any trouble upgrading to Windows 7, as the deadlines don't apply to them: Companies with volume license and Software Assurance agreements are allowed to replace XP with another edition of Windows, assuming the hardware supports the newer.
But consumers and small businesses -- the latter typically purchase PCs and upgrade existing machines much like consumers -- will be in a pinch if Microsoft shuts the Windows 7 ... well, window.
Microsoft did not reply to questions today, including whether it will extend the Windows 7 retail sales deadline.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.
Read more about Windows in Computerworld's Windows Topic Center.