It is sad, but I don't think it was the Microsoft deal that did Nokia in.

Nokia had already been left behind when they finally realized that Symbian wasn't going to cut it against iOS and Android. I think they made a calculated decision: they could try and create an Android device to compete against the likes of Samsung, HTC, Motorola, and LG with basically no differentiation -OR- they could take Microsoft's money and put their hopes on Windows Phone.

If they had gone the Android route, it doesn't seem like they would have gotten a better result. Samsung can make its own displays and chips and that advantage has ground a lot of the competition to dust. LG makes its own displays. Facing this, HTC (who had a nice Android business) has really struggled. Motorola struggled and then got bounced around and still doesn't really make money. Nokia would likely have struggled as well.

Let's look at the Lumia 800 flagship launched in November 2011. The Galaxy S2 was launched in May 2011 with a dual-core processor (as opposed to the single-core Lumia), 1GB of RAM (rather than 512MB), a 4.3" display (rather than 3.7" - and people want larger screens), a 3-colors-per-pixel AMOLED Plus display (rather than the 2-color-per-pixel PenTile on the Lumia), a microSD card slot (while the Lumia had no expandable storage), a front camera the Lumia lacked entirely, and a larger battery. A Lumia 800 Android phone wouldn't have sold well. It was way worse (hardware wise) than a Samsung phone introduced 6 months prior.

Not to go on too much of a tangent, but in a way it was like the Palm Pre. Palm introduced it, but it had a smaller display than the iPhone, underclocked processor, half the storage, 40% thicker, creaky build quality, and the same price tag. Sure, it had the niche feature of the keyboard, but in most ways the hardware was simply inferior. It was easy to write off the Palm Pre as a device that could have been great if not for an OS that wasn't popular enough. If it had run iOS, it would have tanked against an iPhone that was simply superior.

It's very easy to critically acclaim something when one sees one specific flaw that's a dealbreaker. In that case, all other flaws tend to go unnoticed or just get attributed to the dealbreaker. If the Lumia 800 ran Android, it would have been crappy compared to Android phones of the day.

Nokia did a couple cool things like the 41MP Lumia 1020 (or PureView 808). But a camera just isn't enough, especially when wedded to a bulky, underpowered phone with a crappy display. Nokia's hardware was simply poorly matched against what you could get from competitors.

It's always sad to see a brand that once meant so much end up the way it did. But it wasn't Microsoft that did Nokia in. Like many others, they failed to notice how important the iPhone was going to be. Even those that saw the iPhone for what it was (like HTC) weren't spared. Nokia wouldn't have done much better if they'd released their devices as Android phones. They would have been underpowered and overpriced. Sure, some would have bought it for the Nokia name, but not enough. The market was flooded with better hardware. Nokia would have introduced Android phones that would have been mediocre with a premium price. A lot of us remember Nokia fondly and would have rooted for Nokia to introduce something without the dealbreaker of Windows Phone, but we would have been disappointed when we compared a Nokia Android against other options in the market. Maybe it's best that we can just write off Nokia's failure as due to Windows Phone rather than noting that most of their smartphone devices also just weren't great hardware.