Polls narrowed a ton in the final weeks. I think a lot of people simply didn't want to recognize them and considered them outliers. 'Trump can't win!' - well, guess what, he did.
This campaign is going to be a bit different though - people legitimately hated Hillary. I don't think people think the same as Biden - old-fashioned, running on E, etc., but they don't vilify him. Many of Biden's strengths will help him in the Midwest. And don't expect not to hear 'I was a boy from Scranton, PA' all the time - those 20 electoral votes and one more swing state would send him over 270.