No, there were quite a few Symbian models which used capacitive touch, combined with a modern Qt based Symbian OS. Check out "Symbian Belle" and the phone models released with that OS version. I loved my Nokia 603 :)
But I think they only released such models with Symbian for a couple of years, before switching to Meego and then later Windows Mobile OS.
They were in parallel, due to the whole Symbian vs Linux politics at Nokia between teams, both platforms got ramped down to Windows Phone 7 introduction and burning platforms memo.
The N900 was released more for a question of honour than anything.