It doesn't excuse the dropping sales of the 3-Series but I remember reading somewhere (trying to find it) that some dealers are having inventory issues. Again that doesn't excuse the 20%+ drop in 3-Series sales.
But sales in the F30 in the GTA are starting to show. I have seen at least 10+ (only one 335 lol).
Like someone said above, I think introducing the lines has affected sales a bit. With the E90, you had a slew of options from exterior to interior colors/materials/trims. With the F30, you really have no choice.