I feel like the explanations for Trump have been really, really bad. He's had more than an entire term, and I still haven't seen anyone explaining the phenomenon in a way that I found impressive. No-one has given me a model that would have predicted it in advance.
The part where people are dissatisfied and anti-establishment and conspiratorial is the easy part. But why Trump? Why not an eloquent right wing nutjob. Why not someone like in House of Cards? Why not someone who doesn't contradict himself every two sentences?
The point about fiction is important because it's a more honest showing of how no-one gets it. If they did, there would be a story about someone who's like Trump. But there isn't. In fiction, usually either the author is too inept to understand that the other side thinks they're the good guys and just writes the bad guy as trivially evil, or they make a genuine effort and end up with something, well again, plausible. But it's never Trump.