This is a decent video explaining some of the background on why polling got worse from business insider. Essentially it has more to do with conservatives being underreported (they don’t like talking to pollsters) then Gen Z, Millennials, or Gen Xs. Not saying that didn’t play a part, but Nate Silver has talked about this as well in his Silver Bulletin.
Actually apparently it’s the other way. Conservatives are less likely to answer polls. Pollsters have been trying to account for it, but polling has become a very dynamic challenge.