Meego could have been the Android platform of choice
I was in Nokia at the time and it got very ugly in terms of strategy. The strategic blunders that set Nokia up for failure started way before Elop nudged Nokia into the grave. I've always seen the man as the symptom rather than the problem. I'd argue the first blunder was buying into Symbian around the time Linux was obviously the thing to bet on in the late nineties. Nokia bet on the wrong horse; just like many other phone manufacturers that no longer exist.
Maemo/Meego was pretty much exactly the strategy that Android followed half a decade later. It was the right thing to do. Nokia was leading in that space and it was by and large doing all the right things technically with in house R&D. However, at the time Elop joined, it had fallen victim to infighting. Anssi Vanjoki, Niklas Savander and other high placed executives had frustrated its roadmap for years at that point to keep the sinking ship called Symbian afloat. Meego/maemo never stood a chance with those people around.
For reference, Android sucked donkey balls at the time. It was slow, it had major UX challenges, and it's only redeeming feature was that it provided an IOS like touch screen experience in a market otherwise dominated by Nokia with doomed legacy platforms. Nokia had rushed a version of Symbian to market with touch screen functionality. This version was painfully bad. To do it, the geniuses in charge repeatedly ignored a little touch screen based OS called Maemo (later rebranded as Meego) which was essentially debian linux with (initially) an X based mobile UI and a modern Mozilla based browser. This shipped as the N770 in 2006 and had Nokia done the obious things around that time, it could have shipped it as a phone OS very soon thereafter years before either Apple or Google and anything decent to ship. This never happened and that was not an accident.
The ipad took another 5 years to launch and this was 2 years before the iphone shipped; 3 years before Android shipped. Nokia's failure was actively working to frustrate Maemo/Meego every step of the way. Multiple projects for launching products got shelved; several got re-purposed to run Symbian instead. Also Operators hated the thought of a non crippled software platform running things like a real web browser, and the full complement of internet communication tools that they could not control. At the time SMS was how you made money, even bundling an email client or any of the common chat clients was controversial. Never mind the audio and video capable Skype that Nokia bundled with the N800, in 2007. And all Meego products that did eventually launch got marketed as 'developer phones' with no marketing to ensure nobody would buy them. It wasn't until the n900 in 2010 that Nokia even did the obvious thing of bundling the necessary hardware and software to turn Maemo/Meego into a phone, a full four years after the N770 shipped. The n900 was deliberately designed to fail. It had less memory/cpu than it should have had, it had a clunky form factor to make competing products like the Symbian N8 look better. The n8 btw, was originally intended to be a Meego flagship phone: guess what happened there. And for reference, the N8 had an Oled screen and a 13MP camera. In 2010. People are drooling over specs like that today. Imagine that phone running mobile linux with a nice new UI, a developer friendly platform, and android compatibility just a simple OSS install away in 2010. That's what Nokia failed to do.
Now Android and Meego are not two different things. They are essentially flavors of the same thing, which is mobile linux. In fact modern Android includes lots of code that originates from Nokia's attempts to make Meego run well on mobile hardware (drivers, kernel tweaks, etc.). The platforms were in fact so similar that until the first Nexus phone shipped, the only way to run Android was on Nokia hardware: the N800 and N810 were widely used for early android development since you could dual boot it into whatever. The hardware just worked because the kernel was essentially the same for both platforms. Also, you could trivially modify any Meego phone to run Android apps with a few components easily built from source using debian linux tools that ran unmodified on it. I've done so. Nokia had the choice to do that from way before Android launched right until the moment Stephen Elop executed the will of the Nokia board to never allow that to happen. The reasons for this essentially boil down to arrogance, not invented here, and severe & chronic lack of vision throughout senior management. This is what sank Nokia.
Elop actually did a few things right when he joined. He correctly identified the guilty parties and most of them were gone within months after his appointment. Then he killed Symbian, which at that point was sucking up billions in R&D without much hope for ever earning those back. But then he was of course hired to push through the windows phone agenda and he started removing obstacles for that. Killing Symbian was at that point long overdue. Killing Meego on the other hand was a strategic blunder. And killing it's secretive little brother Meltemi was bordering on criminally insane. Google is still trying to execute the strategy with Android Go that Nokia had for Meltemi to ship mobile linux on dirt cheap phones. It got shot down within months of the first product launches.
Of course Microsoft incompetence sealed the deal. In retrospect, outsourcing the demise of Nokia to MS was genius. Nokia essentially got payed to not have to deal with that. MS itself victim of major leadership issues never really figured out how to run a phone division and pretty much strangled it's acquisition from day 1; they never even tried to make it work. The layoffs started right away. To add insult to injury, HMD started shipping only last year and grabbed more market share than windows phone ever had shipping generic android. HMD leapfrogged anything MS did with windows phone in just a few months with nothing more than the memory of a brand name and a couple of generic Android phones made in China.