The unmitigated failure of predictors in this election
I don't think people still quite grasp how disastrous this election was for "classic" predictors:
The Selzer poll
The GDP-Favorability correlation
The 13 Keys
The Washington Primary
Machine learning methodologies
The Primary Model
The Dow Jones Industrial Average
All of them dead wrong.
In the midst of this entire fiasco, polls were probably the best predictor, even though they pointed to a close race and it was more akin to a blowout.