MS borrowed more or less the Nokia name for mobile branding as Nokia is left for its mapping etc services. So, you would also choose to get rid of the naming that doesn't point to your own brand as soon as possible to get public recognition for future creations and innovations instead of boost and keep up the to-be-removed name asap.

And they have to get to that point before the whole windows 10 unite them all things goes on which personally I cant wait for. So much convenience for my pc, tablet and gadgets in general..

Could this pave the way for remote play with microsoft phones? I know I'd be very tempted to buy one as that's one aspect of the PS4 that looks very interesting.

What killed Nokia was the rise of Android, more than IPhone. When Android started to get big, Nokia could have easily jumped aboard and become the unrivalled no 1 among Android manufacturers. Problem was, they had been so huge and were still the worlds biggest handset brand, so they thought that to protect their position the best strategy would be to push their own smartphone OS.

So first they went with updating Symbian (the OS Nokia was already running), then they pushed Maemo, then partnered up with Intel for MeeGoo. Finally they partnered up with Microsoft and ran mobile windows. At that point they had already lost most of their market share for high end phones while chinese handset makers were threatening their market share in developing countries with cheap android phones.

Wasn't the bulk of Nokia's sales back then made from their simpler feature-phones and other non-smart phones anyways?  

Would it really have made a difference if they switched to Android with smart phones being a smaller portion of their sales?

Yes. The bulk of their profits and revenues, however, weren't.

The amazing thing about Symbian was that you could stick it onto a 600 MHz ARM9 processor, and 64MB RAM, and it would still run well. That allowed them to make low-cost, high-margin devices really easily.

Damn shame, I proudly proclaim that I still own a Nokia.