The blue line shows that Nokia's smartphone unit alone had just reported a Nokia-record profit and on an annualized basis would bring Nokia's profits into the Fortune Global 100.
But do you really believe that without any changes, they would have kept on climbing? That consumers would still be buying Symbian devices in record numbers? RIM was once making record profits and selling record numbers of devices, but they failed to see what so many of us outsiders saw; their OS wouldn't hold up against Android and iOS and they needed to adjust for the future market.
Nokia tried to do what RIM failed at. They recognized that Symbian couldn't compete long term (and there's no question that they were right). They could have gone with their own solution (Meego) like RIM is attempting, but I don't see any real reason to believe they would have achieved substantially more success that way. They could have transitioned to Android, and become another hardware player in a very, very crowded Android market, and while that might have been the safer bet, the potential ceiling as another Android OEM was much lower than the potential ceiling of the premier WP7 OEM was.
I don't know that WP7 was the best bet, but I certainly don't see any others that were obviously better. Personally, I probably would have tried to work on multiple platforms (build phones for WP7, Android, and Meego) but I don't know if Nokia was even in a position to try that. I think anything was better than just riding it out with Symbian though.
Of course, the one wildcard here is Windows Phone 8. I am cautiously optimistic that this might be the first decent product to come out of Microsoft in a decade.
I'm going to go ahead and assume you mean the first decent product to come out of Microsoft Mobile
in a decade. Even still, WP7/7.5 was generally critically well received. On its own merit, it is a pretty good platform. The fact that it never grabbed much market share was partially due to its significantly delayed arrival, and partly due to the difficulties of cracking the smartphone OS market these days.