I fully expect to one day see Elvis, Clark Gable or Marylin Monroe and so on in a new movie, but likely commercials will arrive first. Why not, the technology is there or almost there, imagine another decade or two of advances. The family and Estates could benefit of course.
Would it be any good, doubtful (in my mind) as the human element creative life spark can never be replaced. What about an overlay of live actor movements to over come this weakness, I again would say doubtful, unreal is always fake,
However new AI stars are certainly on the way and they don’t sit in their trailers and sulk or make outrageous demands or show up late on set etc.,
Here is a clip of these older actors. They are not that far from going full scale AI movies.
https://www.youtube.com/shorts/3HtpD6fY2LI?feature=share