“You ever think about how in, like, a Tom Hanks movie, everyone lives in a reality in which there’s no such person as Tom Hanks? Because otherwise, people would be mistaking the main character for Tom Hanks all the time? So either Tom Hanks doesn’t exist in the world the movie takes place in, or he does exist but he looks like someone else? I mean, you could have a character break the fourth wall and go ‘Aren’t you the guy from Cast Away? Hey, sign my volleyball!’ or whatever but you can’t really do that in a serious screenplay, so you’re pretty much stuck with that bare minimum level of willing-suspension-of-disbelief before you even get started, unless it’s a period drama or something. And the funny thing is the more famous your star is, the bigger the leap of faith you’re asking the viewer to take when no one in your narrative universe recognizes him, so in a way, paradoxically, great actors undermine their own credibility by their very presence—hey, are you even listening to me? What are you—oh, that’s just Bob. He’s made of bubbles.”
Dan? Yeah, he nailed this one.