Re: Um, no...
You're ignoring how mobile operators purchased phones. The orders were placed at least six months ahead of introduction, so reported sales are more to do with buyer sentiment six months previously, rather than right now (Nokia sold 99% of its product to mobile phone operators, not to users).
The drop in sales is down to the botched N8 introduction, not the Windows memo. I believe that the cause of the memo, and the failure of the N9 to secure distribution goes back a year to when Nokia repeatedly delayed N8, then released woefully un-finihsed software on what should have been a blockbuster device. (Remember that its originally-planned launch date predated the iPhone 4)
N8 burned a lot of operators: it was not just horribly late, but when it did arrive it had very high dissatisfaction rates and returns rates from customers. I had one, and I remember it being awful until the first ("Anna") software arrived eight months after I bought it. It only reached a par with Android/iOS with the "Belle" release in February 2012; a sixteen months after I bought the phone. (But realising that lots of users don't ever update their phone firmware, and lots of users change their phone more often than I do, you can see how badly this product damaged Nokia).
From a developer point of view, the story was equally confused: Qt wasn't fully capable on these phones until later in 2011, but realistically, it was only the Belle release in 2012 with Qt 4.8 that gave developers a painless way to write modern applications, but by then sales were already falling. N8 and 808 PureView made up 70% of my app sales (utilities, not photo related), but my sales dried up sharply in 2013 as those phones came up to contract renewal time, and there was no high-end Symbian device to take their place.
Had N8 been a success, operators would have leapt on N9, as it's a beautiful device, and the first phone to be "better than an iPhone" in terms of aesthetics (the gloss-white version in particular is a thing of beauty). But N8 was a disaster, and the operators were not willing to give Nokia another chance to sell them a pup (it didn't matter than N9 wasn't a pup in the end). Even then, there was a deeper problem to deal with: N9 was a stop-gap, because the "MeeGo" software was nothing like as ready as they let on - in the end N9 was Nokia's UI ported back to Nokia's old Maemo platform from the N900. Had N9 worked out, I suspect Nokia would have still told Intel/LinuxFoundation to get stuffed, and instead put their R&D money into bringing Maemo forward (probably eventually building it on AOSP's kernel)
But all that's "might have beens". The truth was that with no appreciable sales for N9 to pay for its completion (a couple of Australian and Central European operators took it up, but nothing like what it needed for success), Nokia needed something, fast, but their internal R&D could only deliver very, very slowly.