Redditor accurately predicts the election with a Trump W at 312 EC votes 7 months ago. Let's see what his peers had to say at the time.

The Year of the Dragon effect is what most poll nerds were worried about I think. Even aside from Trump in general the Repubs are always underpolled. Nowhere near as bigly as the last 8 years but still enough to be electorally noticeable. However, said under-polling tends to run on a three-cycle repeat. So it'd be under poll, under poll and then on the 3rd electoral cycle the polls adjust and tends to better reflect these hidden Republicans. The best example of this is usually given as 2012 with Romney vs Obama and the former's feeling they'd win with the vibes and the surprise when they didn't. The hope was that such would happen with Trump now and the pollsters would have finally adjusted, or even better from a POV overcorrected, to the hidden election day Trump voter. Such didn't pan out as we see.