Ray Ozzie said it five years ago when he signed up at Microsoft and now, on his way out the office of CTO, he has hinted at it again in a valedictory memo; the future might not necessarily have a big place for Windows unless something pretty fundamental changes.

In the week that reports surfaced about Windows 8, Ozzie dropped some interesting clues as to Microsoft’s conflicted state.

“It’s important that all of us do precisely what our competitors and customers will ultimately do: close our eyes and form a realistic picture of what a post-PC world might actually look like, if it were to ever truly occur,” said Ozzie in a thinly-veiled wail at the Windows monolith he was paid to extol for half a decade.

Post-PC, in this context, means post-Windows in effect, something Microsoft is supposed to be dreading but it is arguable that this world is already with us. This can be seen in new devices such as tablets or smartphones, many of which don’t run Windows, or about new models, such as the cloud, another sphere in which Microsoft is just another company.

Meanwhile, economic power is shifting inexorably from boring enablers such as operating systems to apps and services, the bits people actually use and are willing to spend money on.

It’s hard to see why only three years after Windows 7 the world would need a new version of Windows - Microsoft will know perfectly well that XP dragged on quite well in millions of businesses for eight long years - unless something bigger is afoot.

A 2012 release for Windows implies a change of direction, not merely the addition of some new bits and pieces. Would Microsoft spend large amounts of money to lure a percentage of the user base away from Vista and perhaps Windows 7 with an upgrade?

Given its rumoured investment in an app store, it looks more likely that with Windows 8 Microsoft will attempt to grab back some technology share by making either the OS free, or at least offering a free ‘starter’ version. The latter looks inevitable in some form at some point.

If Microsoft ignores free for too long, it will risk mobile-only rivals such as Android and iOS gaining enough momentum to steal the real jewel, revenues from software developers selling through app stores. That's not an issue right now but could quickly become so if the gravity shifts towards those devices as consumers' primary computers.

It’s hard to see much alternative. As Ozzie himself hints, the weight of developing an operating system to serve increasingly obsolete needs is starting to tell on its creators.

“Complexity sucks the life out of users, developers and IT.  Complexity makes products difficult to plan, build, test and use.  Complexity introduces security challenges.  Complexity causes administrator frustration,” he said in his memo.

It’s made them rich for sure but it could be time detach the albatross.