We may soon be moving into a new political era with propaganda tools so powerful that most historians will be convinced that representative democracy was a historical anomaly of our technological timeline, not an “End of History” inevitability that many either implicitly or explicitly believe it to be.
I don't think AI is doing anything here that wasn't already there. The scary component of AI is that deep fakes will be used to shape public opinion. It could go one of two ways: either people are repeatedly duped by the fakes or they lose trust in media altogether and withdraw from it entirely, for better or worse.
You make it sound like this isn't already known, and already done well before mass media existed. AI is just going to make it easier to pull off tricks that are difficult by last decade's standards.
But people will adjust.