I don't think that's universally true of all AI enhancement though. Information that is "missing" in one frame might be pulled in from a nearby frame. As others have pointed out, we are in the infancy of video enhancement and the future is not fundamentally limited.
If that takes away from the artistic nature of the film I understand the complaint, but I look forward to seeing this technology applied where the original reel has been damaged. In those cases we are already missing out on what the director intended.
In part, we need more vocabulary to distinguish different techniques. Everyone is just "AI" right now, which could mean many different things.
Standard terminology would help us discuss what methods are acceptable for what purposes and what goes too far. And it has to be terminology that the public can understand, so they can make informed decisions.
I also think we already have a bunch of old words for the techniques, like "upscaling" or "statistics". It's "AI" everything now but the old words for the old techniques are waiting to be used again.
If that takes away from the artistic nature of the film I understand the complaint, but I look forward to seeing this technology applied where the original reel has been damaged. In those cases we are already missing out on what the director intended.