The Democrats are running a much better candidate in the Senate race in Arizona. He’s leading by 17-18%, that’s gonna drag Trump down a bit, and Biden’s popular with older voters.
The big difference between this year and 2016 as I see it is the almost certain lack of a winning plurality. When we’ve seen the candidate with lower popular vote total win, it’s always been with no candidate taking the majority of votes. Even if the polls are much worse this year than they were in 2016, Biden is tracking to take over 50% of all votes cast. That doesn’t guarantee an electoral college win, but it makes it harder to lose. Biden’s window looks to be 50.5-57% of votes. If Biden lands on the low end of that, maybe trump squeezes by with narrow electoral wins in key states, but if he hits the midpoint and wins by an 8pt margin, it’s could look like a blowout on the elector map.