His dog won pretty handily in the last election, though. It's not an exact science, but his methodology seemed to eliminate a fair amount of doubt from the equation.
Unlikely, considering there's one every other day
If there's a gradual shift in the polls, I'm not sure what that would mean. Which scenario did you have in mind?
I have a feeling that polling is used now a political weapon not a measure of reality.
(that's actually not the best method to evaluate him, because he provides estimates of chances and could be better evaluated with something like the https://en.wikipedia.org/wiki/Brier_score that checks for calibration as well, but it's more intuitive).