One of the examples was of the nation's leadership.
Easy to say in retrospect. Today no one in their right mind would say Nixon was a better president than JFK - but back then there were a LOT of people saying just that. "Well, I'm open to the idea that JFK was a Papist plant and was working with the mob to destroy America. I've done my own research, see."
There are, however, historians who try to take such retrospective looks at history up to and including the current day. And those have looked at the various presidents and ranked them. And of the five such rankings that have ranked the 45 presidents up to Trump, Trump's rankings have been 45th, 43rd, 41st, 42nd and 44th respectively. Of the two that have included all 46 up to Biden, his rankings have been 14th and 19th respectively. These tend to not mirror popular polls since they are looking at more objective issues like respect for the Constitution, support of our checks-and-balances system and overall improvement in the state of the union.
And it should be noted that even the republican scholars polled consistently put Trump in the bottom five.
That's how we will remember Trump vs Biden in 20 years.