PA - Data for Progress: Biden+7

[President Punxsutawney Phil]

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.inquirer.com%2Fpolitics%2Felection%2Fjoe-biden-scranton-roots-trump-fact-check-20200829.html&psig=AOvVaw0UejLL2CzF3lJmpiqfCYuS&ust=1604447040398000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCLj3g5yF5ewCFQAAAAAdAAAAABAD

[President Punxsutawney Phil]

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.inquirer.com%2Fpolitics%2Felection%2Fjoe-biden-scranton-roots-trump-fact-check-20200829.html&psig=AOvVaw0UejLL2CzF3lJmpiqfCYuS&ust=1604447040398000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCLj3g5yF5ewCFQAAAAAdAAAAABAD

If not for the plagiarism thing I wonder how well Biden would have done against Bush in 1988.

Though it's not all that well known, he was confronting brain cancer at the time. It's likely his health issues would have forced him to drop out regardless of that speech.
If you remove that out of the equation, then it goes down to does he do better, worse, or equal to Dukakis. I guess Bush still wins but by a somewhat smaller margin.