CGI will never fully replace actors, because there will always be some unique talent out there that comes out of nowhere with something new to offer. However, I've thought for a long time that it will be very cool when we will someday be able to see a brand-new movie starring Humphrey Bogart or Fay Wray or other great talents of the past. Or, say, new episodes of the original Star Trek that are indistinguishable from the originals. Of course, a lot of the possibilities would be dependent on the writing talent available and the ability of the audience to want or accept such things. It would probably be a rather niche market, unless the novelty turns it into a fad.