Tumblr used to be a physical place. It was a large theater built inside of a cliff. The cliff was by a stormy seaside town where all of life began. One night, there was a hurricane, and the Tumblr theater collapsed. This unleashed the Tumblr people upon the town, and thus began the world.
You have no idea how big supporter of the theory that the fall from the cliff never happened I am.
Like— The first scene of the series didn't even happen because Will was so immersed in the story he was telling during the lecture. It was only his imagination; at the crime scene Will quickly receives confirmation of all his conclusions, such as the fact that the marriage was tapped and I truly doubt electricians would have been called immediately to the crime scene along with the police, ambulance and FBI. And then he is suddenly “magically” back in the classroom from the house of the victims, when he says, “Everyone has thought about killing someone one way or another. Be it your own hands or the hand of God”.
And since the first scene of the series didn't take place at all, why wouldn't it be the same with the ending? During the battle with Francis Dolarhyde, Will sees him with the wings of a red dragon, something that is unreal. He is also only imagining that.
And the fall is also from Will's perspective, so did it really happen? Or is this only a metaphor for his fall as a human being? He genuinely felt that the brutal pack hunting he shared with Hannibal was beautiful, so he finally accepts his dark nature — he falls as a good and moral man, descending into the depths of crime (ocean).