I'll give them the benefit of the doubt that they can make up some marketshare. In Canada, a majority of smartphone users are still pegged with using blackberries... albeit not necessarily new ones, but blackberries nonetheless. Come time for some of these people to upgrade, they may just plan on buying the new BB again if it doesn't fall flat on it's face in light of the competition. People stay with what they're comfortable with.
I'm also just theorizing (the statistic behind majority of smartphone users still on BBs was something I heard on the radio, so it may not necessarily be true), people might be so relieved to finally be able to upgrade to iOS, Android or WP they won't even consider looking at BB. I know I was quite fond of mine, but there was no denying their current products are a mere shadow to the titans on the playing field right now, hence I couldn't justify the "sidegrade" to a new BB.