The polls
The following is speculation based on logic and reason. No actual facts to back it up.
I think the polls were more accurate than it appears. The right wing in general, and the Trump gang in particular, are NOTORIOUS cheaters. We also know there was a LOT of voter suppression.
Just by way of example, consider the disenfranchised former felons in Florida. They didn't get to vote in the expected numbers because of the GOP Florida legislature's legal voter suppression.
Louis DeJoy did a masterful job of slowing the mails. We will probably never know how many mail in ballots never found their way to their destinations.
Every cycle voter rolls get purged. This year was no different.
Polling places were reduced in numbers in places where Democrats - particularly Democrats of color - would go to vote.
Texas reduced the number of drop boxes to such a level as to be absurd.
These are just a few examples. It defies logic that this didn't suppress the vote.
Were some of the polls overly optimistic? I really don't know
And that's the problem. We REALLY don't know. And we might never. How many of us in the last few weeks, whether seriously or not, were wondering aloud if the pollsters were accounting for cheating.
So yeah. I think the polls were better than they appear right now.
I'm not ready to stick pins in a Nate Silver or Charlie Cook effigy.