No, only for the fact that Windows Phone/Mobile has been in market obscurity for pretty much its entire existence. If not Nokia, i think its possible that we may have seen another manufacturer step up and become the primo Windows Phone handset developer or maybe Microsoft would've went the Google route and have a different manufacturer create a flagship for them each year.
As the OS itself i feel it will reach its plateau in terms of market share in the next couple of years. Unless something drastic happens such as both Google and Apple shooting themselves in the foot, i cant see Windows phone ever challenging them.
I personally just don't see it's appeal, it seems to be stuck in a perpetual state of playing catch up without setting itself apart in any meaningful way. Hardware is lagging behind both iOS and Android Phones, in software we will see the next iteration of iOS and most likely Android before the next Windows Phone Update and of course understandably so, the phone store also pales in comparison.
The biggest annoyance is blueprinting their approach on iOS and making their OS quite restrictive. Do Microsoft even know their own user group?. Enough rambling, at any rate its here to stay with or without Nokia but if they stay par the course, i can never see them being a dominating factor in the mobile market.