Bad news for Microsoft -- Nokia transition to Windows Phone 7 will take two years

A Securities and Exchange Commission document reveals that it will take two years for Nokia to transition to Windows Phone 7 as its primary smartphone platform. But that may be too late for Windows Phone 7 --- by that time, the iPhone and Android could have the market sewn up.
That information, and much else, comes from an annual report document called Form 20-F that Nokia filed with the Security and Exchange Commission. (Here's where to get the document.)
It's a whopper of a document, about 200 pages or so. On page 13 it has this to say:

We expect the transition to Windows Phone as our primary smartphone platform to take about two years.

That means some time in early 2013. The mobile landscape changes so quickly, it's hard to know what will happen in the next two years, but there's one thing that's quite likely: the iPhone and Android will further cement their leadership between now and 2013. Waiting two years for Windows Phone 7 to become Nokia's primary smartphone platform is quite problematic for both companies.
In the document, Nokia lays out its overall transition plan:

While we transition to Windows Phone as our primary smartphone platform, we will continue to leverage our investment in Symbian for the benefit of Nokia, our customers and consumers, as well as developers. This strategy recognizes the opportunity to retain and transition the installed base of approximately 200 million Symbian owners to Nokia Windows Phone smartphones over time.

On paper that sounds nice and neat. In the real world, though, it may be impossible to do. Symbian looks and works nothing like Windows Phone 7, so it's not clear exactly how Nokia will be able to turn Symbian customers into Windows 7 customers.
In addition, if customers know that Nokia is going to eventually quit on Symbian, will they be interested in buying Symbian devices in the next two years?
Developers will be caught in a worse bind. Will they want to develop apps for Symbian, knowing that it will have a shrinking customer base? And because Windows Phone 7 won't have a sizable customer base, can they afford to develop for Windows Phone 7, hoping that revenue will roll in two years down the road?
If the transition were a shorter one --- a year or less --- all this would be relatively easy to do. But a two-year transition makes it all much more problematic. Microsoft would be in a far better position if Nokia moved to Windows Phone 7 well before 2013. It's going to be a nail-biting two years for Microsoft until the transition is complete.