After four years, the 2020 polls pick up almost exactly where they left off in 2016.
Here's how the race has changed, or hasn't
https://www.nytimes.com/2020/04/22/upshot/polls-biden-trump-election.html?action=click&module=News&pgtype=Homepage

And there's basically a whole piece-within-a-piece here on seniors, discussing the many factors possibly at play:
--Generational change, as boomers now 60% of senior RVs
--Coronavirus
--Biden relative favorability
--Polling biases, as many polls include too many old women

And, here's an out-take. Change from 2012-->2016 compared to change fro 2016-->2020, using same method