If you were someone who was going to vote for Trump and for the last 4 years you were continually portrayed in the media as a deplorable racist nazi would you be super excited to share this with a random stranger?
If, of people saying they’ll vote A, normally 100% will actually vote, and of those saying they’ll vote B, normally 80% will actually vote, the models that predict election results from poll result will correct for that.
So, if the poll says it’s 50/50, the model will predict a clear win for A, with about 55% of the vote.
If turnout increases, all extra voters will vote B, but the model might still predict that 55% (I kept the example simpler than reality will be)
[0] https://www.politico.com/news/magazine/2020/10/29/2020-polls...