But writing in itself has been obviously untrustworthy since it started existing - something being written down doesn't in any way make it trustworthy. The fact that audio recording, photography, and video enjoyed this undeserved reputation of being inherently trustworthy was an accident of technology, and has come to an end.

Just like with writing, though, this doesn't signal a real problem of any kind. You should still only trust writing, audio, or video based on the source - as you always should have. All that's ending is the era of putting undue trust in audio/video from untrusted sources.

Of course, the big problems will be in the transition period, when most people still think they can trust these sources, or will think they can't trust actually trustable sources instead. But this will be temporary as things readjust.

And again, audio and video have been untrustworthy for a long time, for sensitive things. You should not have trusted video in itself even in the 40s - 50s, and audio and photos probably even in the 1910s were already somewhat easily manipulated. And this is even true in a legal context - audio or video evidence is not evidence in itself, it is only part of a witness testimony who can attest to the provenance and veracity.