Trump does still lead in our national average — however narrowly. But the bigger problem for Biden though is that elections in the United States aren’t determined by the popular vote.
That's a problem for all of us. If the president were elected by popular vote, Trump would never have been president.
Neither would George W. Bush. Republicans have won the popular vote only once in the last 32 years, and that was Bush as the incumbent in 2004 - which wouldn't have happened had Gore been the incumbent.
This is a center-left country, with an election system that gives extreme right-wingers oversized influence.
The left is larger than the right, here. How does that make it not a center-left country? We're sure as hell not a right-wing country, and much of our government is an accident of antiquated and stupid systems, not a true reflection of the people.
The election system distorts the vote quite dramatically in the US, that's true.
However, depending on where you're from left has quite a different meaning from what Americans mean when they say left. E.g. the Democrats don't want to dismantle capitalism or expropriate real estate companies (the city of Berlin seriously looked into this option). Centerleft has a similar shift in meaning in other countries.
Presumably in much the same way that toddlers can't win a high school scholar bowl. Just because one side or type of idea is a clear winner doesn't mean it's not a fair system.