Unscientifically, I think it's like this:
20% Clinton fatigue (Wolf Blitzer and the True Believers believed the Omni-exoneration narrative, but there was a cumulative effect to the scandals; they all kind of fit a credible narrative).
10% MSM fatigue (spite-vote that W&B talk about)
20% Trump-as-strongman-will-Hulksmash-their-problems
20% Obama fatigue [if you'd like to call this raciosm, do so now]
20% Obamacare
10% {And you will love this but I'm just being real} BLM/Kapernick fatigue. A lot of Amuricans still believe in America (I realize that the OGB Left looks down at this notion, but it's a rich-man, poor-man; You guys are too cool for America!, and I get that, but there are places on Earth to live other than Western and Northern Europe, and by comparison to most of the globe, America ain't what's wrong with the world), and I think the persistent drumbeat of negativity from the left had an accumulated effect. This election was an outlet for the negativity.