It wouldn't need to be such a radical transformation. His 2012 self (the one who owned Paul Ryan in the Vice-Presidential debate) would win comfortably.
Back in 2012 his detractors were saying he was showing signs of being too old, that he had gone downhill a lot over the last decade.
You can pick any year in Biden's old age, and in that year people are always saying he was fine a few years ago but now he's senile. And before he was old, they were just calling him stupid anyway. I remember threads here in 2008, 2012, and 2016 about how Biden was just too old and slow-paced nowadays.
It’s obvious to anyone who isn’t a diehard fanboy of Biden that he has fallen off substantially since 2012. At this point just successfully reading off a teleprompter with no major gaffes exceeds most people’s expectations.
You're demonstrating my point. It was "obvious" in 2020, 2016, 2012, and 2008 to his detractors just as it's obvious to them now.
This. Biden has always been a gaffe prone politician. This was well known of him, and given how prominent he was previous to running for POTUS I’m surprised how much it shocked people once he got in.