You pretty much got it: you enjoying a coke, driving the new car, you and your significant trading engagement rings, you in a film trailer interacting with the film's stars... The personalization can be anything from simple ads to political messaging. The trick is getting a major brand to want to do such a project. It's a completely new idea, and that requires more than a few people sticking their necks out and taking some risk. My experience has led me to believe the advertising agencies really need strong assurances to take the risk of doing personalized advertising. Consumers are used to feature film quality VFX, meaning their eyes are moderately sophisticated when looking at digital characters. The production quality required will require investment and iteration to get the personalization production pipeline correctly generating likenesses of real people that "pass" and do not look like a cheap gimmick. To date, every potential agency and production partnership I was able to begin to piece together became a no-go due to one or the other wanting to go cheap or do porn. Neither of which really work, economically or financially.