There's a lot of debate about how good the polls and 538 have been is this election in comparison to the betting markets. While it's hard to compare it when just looking at percentage for Biden winning, it would be possible to calculate the Briers score by looking at all US states. Did anybody do the math?
Looking at states still throws away information. Trump lost by slightly over a 0.6% margin in the states that he'd have needed to win. The polls were off by slightly under a 6% margin. If those numbers are correct, I don't see how your conclusion about the relative predictive power of 538 and betting markets can be very different from what your conclusion would be if Trump had narrowly won. Obviously if something almost happens, that's normally going to favor a model that assigned 35% to it happening over a model that assigned 10% to it happening. Both Nate Silver and Metaculus users seem to me to be in denial about this.