CGI will never replace actors, no matter how convincing they may be. There wouldn't be any point in it, for one. I can understand in action or sci fi you might use CG charaters for some scenes, or for characters that can't be played by humans, but what about dramas? Romance? Period pieces? Why would you bother? Plus, a huge part of cinema in Hollywood is star power. People go to see films for the actors that are in them. Studios pay millions of dollars for actors like Arnold Schwarzewhatever (sorry, no idea how to spell that one), Sylvester Stallone etc. Is that because they are more convincing actors? I don't think so. Digital animation, like any form of animation, has it's place, but will never replace live action.