It will turn out that AI deepfakes will matter less. What will matter more is that their very existence will allow people to discount probably true things.
"Scholars who study deepfakes have pointed out that the existence of the technology means people can try to claim authentic videos and photos are fake. Back in 2018, law professors Robert Chesney and Danielle Citron even coined a term for this phenomenon, calling it, “The Liar’s Dividend.”"
https://www.npr.org/2024/08/14/nx-s1-5072687/trump-harris-walz-election-rally-ai-fakes