Land doesn’t vote, people vote. Bear in mind that those Biden counties represent 60% of the U.S population.
While it’s true that land doesn’t vote, the best way to understand the purpose of the Electoral College is to look at the counties won on a map of the whole country and realize that the Founding Fathers wanted the president to be someone who had widespread appeal.
Also, there’s no way Biden got so many more votes than Obama when the press and most Democrats were so ga-ga over Obama (Mrs. Bill Clinton excepted.).