Comment by tmnvdb
My understanding is that the microsoft partnership was more like a late last ditch effort.
The market was changing to one where hardware was produced in asia and phones are loaded with ecosystem-centric software from Google or Apple (the real game changer, the app store, was launched next year).
Nokia did not really have a place in either of those and did not manage to adapt to this fundamental change. They did actually manage to adapt to the UI revolution of the first iphone.