>half the country fell for the lie

The fact that you state half the country is already rather telling. People believe bullshit lies they want to believe. That will always be true, with or without video. There is no extremely convincing misinformation. Once it becomes blatantly obvious that everything is false as opposed to the current climate where there's a debate to be had about the percentage of falsehood, the medium will simply become irrelevant. The weight behind it is that it comes from a trustworthy source to those people, not that it's organically based on some kind of proof.

>Gee.. Maybe it because they could actually rely on photographic, video, and audio evidence back in that era?

Yeah, the photographic video and audio evidence that was everywhere in all of the human history.

And people believed what trustworthy media told them, yeah. That had it's negatives but was all in all a functioning system that typically showed less cracks then the information system of today. These outlets will still exist and as i said before, likely get a lot more pushback for lies then in the current system, as a general standard of truth would arise from the common media standard. Opinion based media would be crushed under the weight of fact based media and an outlet reporting contradictory facts would quickly be singled out and discarded. Of course crazy conspiracy theories would still exist. It'd probably put a hard stop on dumbass conspiracy theories that are based on communities like Qanon since social media would by and large not be a thing.