He may not be an infallible savant, but his perspective has some credibility. I’m not sure what you’re talking about when you say he flip-flopped. I saw him saying Trump was going to win based on his model and sticking with it while people were laughing at him during that election cycle.
He was mad hedging, and he admitted that his model would shift to a Clinton win once Gary Johnson's poll numbers dropped below 5%:
"Given all of these exceptions that Donald Trump represents, he may well shatter patterns of history that have held for more than 150 years, lose this election even if the historical circumstances favor it."
"I believe that given the unprecedented nature of the Trump candidacy and Trump himself, he could defy all odds and lose even though the verdict of history is in his favor. So this would also suggest, you know, the possibility this election could go either way."
"Qualification number one: It takes six keys to count the party in power out, and they have exactly six keys. And one key could still flip, as I recognized last time — the third party key, that requires Gary Johnson to get at least five percent of the popular vote. He could slip below that, which would shift the prediction."
"As people realize the choice is not Gary Johnson, the only choice is between Trump and Clinton, those Gary Johnson supporters may move away from Johnson and toward Clinton, particularly those millennials."
https://www.washingtonpost.com/news...g-down-on-a-trump-win/?utm_term=.c92bdd8dd9cd
So one of his "keys" for Clinton losing was the assumption that Gary Johnson was going to get 6-7% of the vote. That ended up being way off. Once Gary Johnson slipped below 5% (he ended up with just 3% in the end), then his model would have predicted a narrow Clinton victory.