The Maemo platform (what was shipped in N900, and later joined with Intel's Moblin into MeeGo) was based on GTK+ and related technologies since the days of Nokia 770 tablet (https://secure.wikimedia.org/wikipedia/en/wiki/Nokia_770).
From that POV, you could say Nokia abandoned a lot of man-years of Maemo toolkit work becaues they wanted to use Qt so they could say it targets all Nokia devices.
Now with no plans to put Qt on WP7, it's kind of ironic :-)
Interestingly, at the same time you can write fully-integrated software on Maemo with Qt, even though the platform itself is GTK+. There was no need for a rewrite to achieve a consistent developer story.
From that POV, you could say Nokia abandoned a lot of man-years of Maemo toolkit work becaues they wanted to use Qt so they could say it targets all Nokia devices.
Now with no plans to put Qt on WP7, it's kind of ironic :-)