But why does it take so long to reverse?? I mean the Sun reverses polarity every 11-12 years and that is when its activity peaks. Why is the reversal process so slow on earth?
The process that occurs on the Sun during the solar cycle isn't the same as the process of an Earth pole-reversal. And in any case Earth is not nearly as energetic as the sun, and isn't made of charged particles, so our magnetic field isn't nearly as dynamic, and changes take much longer to occur.
And why do they make these documentaries so dramatic? They exaggerate the phenomenon to an extent of causing public hysteria and panic!
That's the media for you. They have to capture your attention somehow.