Discussion: Election polling, why is it getting worse?

I’m working on a sociology multi-part question and need the explanation and answer to help me learn.

. What are two reasons that, in the 2016 and 2020 Presidential elections, the polling did not do a good job of predicting the eventual voting patterns in states. 

I love a good conspiracy theory, but there are actual methodological reasons why this happened. 

https://www.npr.org/2012/10/30/163950603/why-do-el…