The article seemed like a lot of babbling from someone who spent a very short time at a company who's problems started over ten years ago. An insight here or there, yes.
Nokia for much of the later 90s and early 2000s was the handset of choice for the enterprise in Europe. Blackberry ruled the US market. At the same time, they had an amazing market opportunity in basic handsets in the US, Europe, and emerging markets. Nokia was the go to phone for "just working".
Things changed in 2007 w/ the iPhone and the subsequent drive towards an app based smartphone ecosystem. Before the iphone, there were "smart phone apps", but they were a small franctional percentage of what is available now. iPhone and Android have helped this app-based economy.
Nokia never got there. Developing on Symbian is a royal pain in the backside. Despite their working w/ Borland to develop tools for development, a simpler tool chain never emerged. Furthermore, a lack of an app store (ovi was late to the scene) didn't help things.
Nokia failed to adapt to this new world and proceeded to try and develop OSs at a glacial pace. The hardware has always been great, but an OS with an app (and developer friendly) ecosystem never emerged.