Clooney could have done Hancock, and Edward Norton could have done American Psycho. But OJ as the Terminator and Robert Redford in the Graduate sound ridiculous.
Terri Nunn auditioned for Leia, but thought her singing career was more important. All the better, since when I watched Star Wars as a kid I paid attention to the story. If it had been Terri Nunn all I would have been thinking about is “When do Leia’s clothes come off?”
The one person I’ve seen who missed many roles is Nick Nolte. Characters he turned down or was passed over for: Han Solo, Indiana Jones, Superman, Willard in Apocalypse Now, Deckard in Blade Runner, Rambo, and others. Notice he seems to get replaced by or lose to Harrison Ford a lot. Sad, he’s a better actor than the people who got those roles.
I think Nick Nolte is a good actor, but there’s something about him that seems to add a “non-serious” element to many of the serious roles he plays. Maybe it’s because I can’t helping thinking of his various mug shots whenever I see him in a movie.