Another thing often discussed is how the last few big elections and votes in the US and UK have confounded the pollsters and predictors.
I'm just going by the fact that - simplistically - electorate is made up of Trump's base that will never waver, Dems who will never vote for him and a number of undecideds/floating-voters, I think that Trump's actions while governing have been such as to alienate all except the first group. I just can't see anyone who voted Dem last time and who is in their right mind thinking "Ooh, I like what he did when he stole from his charity, think I'll switch to him" whereas there must be a few moving the other way.
To me Trump will lose the popular vote by some margin, the only question is, can he cheat enough to get close enough to wangle something out of the electoral college. I hope not, but who knows.