Nate (or rather, the 538 model). didn’t make a 96% chance of victory prediction. It at most went up to around 88% right after the debates where Trump made a fool of himself and the Hollywood Access Tapes were released. But even then, Silver cautioned in an interview that Hillary’s support among certain groups was soft.
I’m honestly not sure when the Democrats will have a solid win again. Recently the electoral college has tilted against us and Trumpian populism has taken grip over a large portion of the country. Fewer and fewer voters are up for grabs. It took the unpopular Iraq War for Obama, who was also a very gifted candidate and campaigner, to get a 7.2% lead. I expect a lot more repeats of 2020, where Biden only got a 4.5% lead despite Trump’s poor leadership during the COVID-19 pandemic. A slightly closer race would have had Biden losing key swing states and the election.