I see what you're saying, but look at it this way.
I am a HUGE fan of the Lego Movie.
And for Christmas, my brother and I wanna get: The Construct-o-mech; the Super Secret Police Ship; and Benny's Spaceship, Spaceship, SPACESHIP!!!
And if Bionicle were to come out before Christmas, everyone who has already planned on getting stuff like this would be pressured in their Purchase decisions.
With BIONICLE coming out in Janurary, people will have time to collect the sets for the rest of the year.
Besides, my birthday is in Feburary and I plan to get the sets then, at a Lego Store.