Qt is the platform, it shouldn't matter to end users what OS their device runs - they only need to know that the more they pay for the hardware, the better/more advanced features they will get (S40 budget/feature phone, Symbian mid-range, MeeGo high-end). Heck, you could even throw Android and WebOS into that mix. All these devices could be running Qt, the only differences being package management and re-compilation of any binaries for each platform (much of which could be automated, possibly even eliminated).

This was (almost) the original Nokia plan that - I'm pretty sure - Microsoft did all they could to kill off since Qt would have been yet another significant threat to their mobile aspirations, and perhaps by extension in the longer term their desktop development business.