Right now Nokia is counting on selling its cheap line of devices, including the feature phones, Asha line and cheap Windows Phone smartphones. Where they fail greatly is selling their flagship smartphones. That is because they are counting on features that are not that interesting to the public. Sure all the devices - even the cheap ones - are well built. But there are other things to consider.
Microsoft buys Nokia. Nokia wants to go back on its own. Either the case the company has already announced it will abandon its Nokia OS (previously known as Symbian). And with that lost a great deal of fans. I can only think of those owning a smartphone like the the 808 PureView - a very expensive piece of hardware. As for the Asha line - they are going forward with that for the cheap devices based also on Java for apps and games. Asha version 2 is already running on the newest line of devices.
With Windows Phone 8 Nokia is doing OK only when it comes to the cheap line of devices. The Lumia 520 is an unexpected success in terms of sales for the company. Along with offering some good cameras on the Lumia line and their own navigation system that has been positively appreciated - one thing you can be sure is Nokia isn't going anywhere. They just need to keep a steady line, concentrate on jus 2 -3 at most OSs and bring devices with even better designs and cameras. After all those are their main assets. But hey, thouse are only my thoughts.