I define close as "the number of votes needed to change the outcome is small". It was microscopic in 2020.
But that's not a useful metric because of how elections work in the EC dynamic. It always only takes one drop each to make a row of full glasses overflow, but it makes a big difference whether we are filling them with an eyedropper or a firehose.
I understand your point, the three closest States had relatively close margins in Biden's favor. Point taken. However
that only matters because of the EC,
which wasn't close. Those three states were close
in popular vote, but the national popular vote wasn't close. So the election being "close" is an illusion created by the EC.
So on the one hand, if I say "The election wasn't close, Biden won by 7 million votes, with most votes in history and the highest percentage margin of victory in over 80 years", you will, understandably say "But vote totals don't matter, all that matters is the Electoral College". But then when I say "I agree, and the Electoral College wasn't close either", you then reply "But look at the vote totals!"
This is the point I kept making during the election about the national polls and the percentage margin lead that Biden had. I kept making the point over and over that if Biden had a certain percentage lead in the national polls, that would be a strong indicator of how he would fare in the electoral college, because the numbers are linked... and if Biden's lead slipped underneath a certain percentage, he would lose the EC, despite winning the popular vote, because again... one is predictive of the other. Once Biden's national polling lead got to a certain threshold, it was an indicator that the races in the close states would swing in his favor and vice versa.
The bottom line is Biden and/or "Not Trump" was way more popular, overwhelmingly so.
That's why he won all the "close" states.