But even if Biden were to win just the states where he led by 5 points or more, he’d still get over the 270 electoral vote mark. That was simply not the case for Clinton in 2016.
More interesting is what happens if you look at the specific state errors that occurred in 2016. The errors were biggest in the Great Lake (Rust Belt) states. They tended to be considerably smaller in the Sun Belt.
As The New York Times’ Nate Cohn points out, Biden would get more than 300 electoral votes if the 2016 errors repeated themselves exactly in 2020. It’s not as if Biden would still be ahead by a lot in some pivotal states with a 2016-like error. Even so, he would be ahead by at least 2 points in states totaling 270 electoral votes if the 2016 polling errors repeated themselves exactly.
Now perhaps you want to argue that being ahead by just 2 points isn’t a lot. But keep in mind, we are talking about Trump needing an additional 2-point error on top of an already large error.
Trump would, in other words, need a large miss to take the White House in 2020. That could happen, though it’s unlikely.