N9 development was stopped by the management despite the success in the market: all Nokia phones started moving to Windows as the "strategic" platform due to a new CEO who joined from Microsoft.

Yes, previous management messed up before that point too (they did not ship N700 with GSM chip and marketed it as "internet tablet" so as not to jeopardize their Symbian phone sales, only adding it to N800 and beyond, and then Apple turned their iPod Touch into iPhone and stole their lunch), but they finally figured out a great phone, and then... pivoted.