Animations have been used in commercials for a long time. At least I don't recall Captain Crunch being a real person ;) Or Mr. Clean for that matter. What you are really asking is whether CGI will ever replace humans in cases where the advertiser wants a living person advertising their product. I can think of a lot of reasons that could happen besides just cost when animation gets good enough to fool people into thinking it's real. And it wouldn't just be advertising. I think Disney would have loved using a Hannah Montana that didn't grow up into Miley Cyrus, and let's not get started on the Mousketeers. Humans have personal lives, get into accidents, grow old, and do various other things that drive corporations nuts. Any time you don't have to meet that vision in person there are a whole lot of reasons to use CGI. When the time comes.