You are missing a couple of important facts; the NASA video explains that tailplane stall recognition is not applicable to aircraft equipped with powered flight controls (rudder and elevator on the Q400), Aircraft equipped with a T-Tail configuration are not nearly as suceptible to tailplane icing like the SAAB. It is also very likely had the Captain released the controls at the sticker onset after applying power the airplane wil naturally seek it's trimmed airspeed after a series of convergent phugoids, because it is dsigned to be dynamically stable in the longitudenal axis. Basic aerodynamics all pilots are taught and should be able to apply. We will never know why both pilots lost their SA! but we know the outcome...