There was a brief time (maybe 100 years at the most) where photos and videos were practically proof of something happening; that is coming to an end now, but that's just a regression to the mean, not new territory.
The important number here isn't the total years something has been true, when talking about something with sociocultural momentum, like the expectation that a recording/video is truthful.
Instead, the important number seems to me to be the total number of lived human years where the thing has been true. In the case of reliable recordings, the last hundred years with billions of humans has a lot more cultural weight than the thousands of preceding years by virtue of there having been far more human years lived with than without the expectation.
just some google link about the issue: https://rarehistoricalphotos.com/stalin-photo-manipulation-1...