Isn't that already the case in background actors that are not in focus in many cases? There are a lot of examples on youtube, where background actors are either

Isn't that already the case in background actors that are not in focus in many cases? There are a lot of examples on youtube, where background actors are either digitally cloned or entirely created only digitally. This goes back at leat a decade, only a matter of time until it will move into the spotlight more. Planet of the Apes is a recent example of pretty impressive CG characters where only movements come from real actors, but of course these are not humans and still look CGish.