Perhaps the biggest miscalculation of all can be found in the NBC exit polling data. 73% of the country were concerned that democracy was being threatened in this country. Of course, we all know how the Dems have been pushing that narrative non-stop, especially over the last year.
Trump won those voters 51-48%, and the more concerned that group of voters were, the more Trump's margin increased.
https://www.nbcnews.com/politics/2024-elections/exit-polls