John Wayne westerns explained brilliantly by Roger Ebert. I love John Wayne westerns. What that says about “moi” remains to be analyzed.
In this case, the story itself doesn't matter much. We go to a classic John Wayne Western not to see anything new, but to see the old done again, done well, so that we can sink into the genre and feel confident we won't be betrayed. To some degree Wayne movies are rituals, and so it is fitting that they resemble each other. "El Dorado" was a remake of Hawks' "Rio Bravo" (1958), and "Rio Lobo" draws from both of them. (It is said that when Hawks called Wayne and offered to send over the script, Wayne replied, "Why bother? I've already made the movie twice.")