And in the case of many others, it makes a very significant difference. And a codec doesn't have enough information to know.
Imagine a criminal investigation. A witness happened to take a video as the perpetrator did the crime. In the video, you can clearly see a recognizable detail on the perpetrator's body in high quality; a birthmark perhaps. This rules out the main suspect -- but can we trust that the birthmark actually exists and isn't hallucinated? Would a non-AI codec have just showed a clearly compression-artifact-looking blob of pixels which can't be determined one way or the other? Or would a non-AI codec have contained actual image data of the birth mark in sufficient detail?
Using AI to introduce realistic-looking details where there was none before (which is what your proposed AI codec inherently does) should never happen automatically.
Imagine a criminal investigation. A witness happened to take a video as the perpetrator did the crime. In the video, you can clearly see a recognizable detail on the perpetrator's body in high quality; a birthmark perhaps. This rules out the main suspect -- but can we trust that the birthmark actually exists and isn't hallucinated? Would a non-AI codec have just showed a clearly compression-artifact-looking blob of pixels which can't be determined one way or the other? Or would a non-AI codec have contained actual image data of the birth mark in sufficient detail?
Using AI to introduce realistic-looking details where there was none before (which is what your proposed AI codec inherently does) should never happen automatically.