I worked in Nokia at the time this happened and saw from the inside how the company was ran into the ground by internal incompetence, years of mismanagement, arrogance, and ineptness.
Stephen Elop gets the blame for this often but he was merely the messenger boy. Put there by a board that allowed all this to happen long before he was installed to quickly execute what had been decided by that board. And that board was lead by its former CEO Jorma Ollila. Who made Nokia big in the nineties and was instrumental in its demise and involved with all the key blunders in the ten years prior to selling the remains of the phone division to Microsoft.
Nokia thought they were being smart by jumping ship to Microsoft's Windows Phone. But the reality was that was the merely the latest in a series of very misguided moves that started in the late nineties when they failed to see the potential of Linux and bet on Symbian instead. Nokia's leadership had an enormous blindspot when it came to software. It's technical leadership consisted of people with radio and electrical engineering backgrounds. They were simply incapable of seeing what was happening very clearly in the industry in the late nineties. Linux was happening in a very big and obvious way. And it was inevitably going to run on phones. That was clear in 1999 and a reality before the first Symbian phones even shipped.
By the time Google bought Android, backing Symbian had very obviously been a bad move. By that time there were so many people trying to get Linux going on phones that it was just a matter of time before someone succeeded. Google wanted in on the action. Linux/Android was their quick way in.
Nokia was struggling to get Symbian to market while all that was happening. It was crap. The first versions crashed all the time and were really sluggish and klunky. Incidentally, Nokia actually killed a touch screen platform for Symbian that they never launced. In 2005 as the rumors about the iphone started circulating. Nokia was instead obsessing over flip phones and saw Motorola's razr as its biggest threat. So, it killed the touch screen platform mistakingly thinking that it was not needed.
All this was so obvious that in fact a department in Nokia took it upon themselves to build a Linux based platform. Maemo. The first product launched in late 2005. It was based on Debian Linux and featuring a UI built using GTK and a web browser that was based on Mozilla. A full six years before the first Ipad launched, Nokia had an linux based tablet with a touch screen. Exactly the right kind of thing to be bringing to market around then. Except the Nokia management was completely blind to this and kept on favoring Symbian.
Years later when Google finally unveiled Android after Apple launched the iphone. Google had been relying on a lot of the R&D that went into Maemo. As they lacked a phone until they launched the first Nexus, they even used the N800 as a development platform for Android. There was even a port of Android that you could boot on an N800. I know because I had one and tried it.
Google bought and eventually launched Android between 2005 and 2009. But it was Nokia that was doing a lot of the heavy lifting on kernel development. By 2008 Nokia had a very coherent platform strategy for launching a Linux based range of phones. By 2010 that strategy included a UI platform (QT), Meego, and a then still secret entirely new platform based on Linux aimed at feature phones that got unceremoniously cancelled in 2012 without a product ever having been launched.
Nokia's failure was favoring Symbian throughout this chaotic period until it was crystal clear that the market was never going to favor Symbian and that all attempts at open sourcing it and fixing it were simply not succeeding. By then Google was succeeding with Android and Apple was growing market share with the iphone without Nokia ever having gotten serious at even trying to compete with the platform it had all along.
The thing is, it took Google many years to turn Android into a decent platform after they launched it. The first versions had all sorts of issues with poor UX, poor performance, stability, security, etc. Manufacturers used it mainly because Symbian and Windows CE were worse and there wasn't much else in the market that they could use. And they were hopeless at doing software themselves. And while the iphone was popular, the first versions were pretty limited in features.
So, Nokia had a chance for several years to launch a platform based on the same Linux kernel that Android was using that they were using in Meego. They had all the pieces to pull that off; including a large base of existing users that still loved their Nokias. But they blew their chances because internally Symbian was the darling and people backing that spend years frustrating and delaying Meego.
Phones that were intended to launch with Meego in fact launched with Symbian. They bought Trolltech (QT) to fix the UI for Meego but that turned into a project to fix Symbian instead. The original Maemo devices were using GTK. That move delayed a Meego launch by three years or so as the UI platform they had was scrapped in favor of QT. The only Linux phone with QT that ever launched was the N9. And only after they decided to kill the platform and fire the team. The N900 before that (2009) was still using GTK. It was fine. I had one. Pretty awesome device at the time. Way nicer than anything Google was shipping. But it was very obviously a developer phone and never aimed at consumers ,and a bit klunky, and limited from a hardware point of view. Almost as if they wanted it to fail.
The N9 was launched after Stephen Elop had been appointed around the time of this silly memo. The decision to can it was of course taken before he joined. One of his first moves was killing that at the same time as he was killing Symbian. Basically, he killed Symbian, Meego, and Meltemi (the linux based feature phone platform) to make room for windows phone. In a bizarre move of defiance, Nokia actually managed to launch an Android phone just before MS acquired the phone unit and promptly killed that.