This could be an autismal take, but I'd argue the culture wars broke this model and broke the the whole "incumbant usually wins" prophesy, probably still valid for undecideds, if anyone can find a real one anymore, but 2016 was the start of a different dynamic where both sides are in complete information bubbles, 2020 is much worse, and the election comes down to turnout.
When this model mattered, Biden's campaign crumbled because he plagiarized some phrases, now footage of him that Twitter considers child sexual abuse can't even hurt him. Same with Trump, the smallest scandal would of ruined his campaign in the 90's and 2000's, but look at him now after 4 years of weekly scandals, fake or real.
In this case, objective markers like those keys mean nothing if the media lies about them, Trump could have all or none and the media can say the opposite, or each side can think the opposite, regardless of the reality.