An environment where it's become difficult to tell what is true and what isn't. You could also phrase it as, what's real and what isn't. An epistemic crisis. I think we crossed into a post-truth world 7 or 8 years ago (it's been in process for at least a couple of decades) so it's not like AI precipitated this crisis, but it will accelerate it to new levels.
Yes, access to truth lies on a spectrum. Post-truth references pop up in this moment particularly due to the quantum leap in dis/misinformation. Any layperson, anywhere, can soon convincingly fabricate media of nearly any form: images, video, audio, legit-looking websites, etc. To me, it's justifiable to regard 2023 as an inflection point for truth. My predictions are less catastrophic than many worried folk, but I definitely see why the post-truth moniker is appropriate. Crazy times!