[rsynnott]

538 et al don't, as a general rule, run their own polls. In 2016, some swing states were poorly polled, so they were flying kind of blind on those.

And, of course, a few tens of thousands of votes different on the day, below the margin of error of any poll, and no-one would be bothered about them. In a way, 538 can't win here; they said "there's a 30% chance of this thing happening", it happened, based on differences below the resolution that they could even see at, and everyone's annoyed with them.

[dane-pgp]

If differences below the resolution that you can see can cause the opposite outcome to happen, then perhaps an estimate of "30% chance of this thing happening" should be paired with a "1% chance of that estimate being correct".