if you looked at nokia's plans for the future you'd know that their planing on 3 platforms
S40 - low end cheap mobiless
Symbian - midrange smartphones
Maemo - high end sophisticated mobile devices

symbian is projected to be their largest market while S40 is going to grow alot more as they expand more into poorer countries.
maemo is projected to expand slower but they plan on releasing 1 maemo 5 device this year and (if i recall correctly) have 4 next year.