A TV biography of John Wayne claimed he was actually imitating Wyatt Earp. That might have been alright if he was acting in a roll as Wyatt Earp in a movie but he wasn't. Real actors changed their characters to fit the various roles they played, instead of having movies written around the only character they could be. I know many westerns had the same basic themes but a good actor could make a lot of difference.
I do like "The Man That Shot Liberty Valence", other than John Wayne's character, and most of his movies could have been great if they had someone else star in them. In spite of his poor acting he was a major box office draw, maybe people thought all cowboys were supposed to be the same as Wyatt Earp.