(or "All The Old Familiar Places")
The main thing to keep in mind when reading Jonah Hex, DC's classic Western comic, is that it came out in an era where Westerns were generally more popular than they are today. (Not to say that the Western has disappeared, but it's certainly not as common as the early 1970s, when Hollywood was still churning out Westerns relatively frequently, and when TV was syndicating re-runs of old Western series and old Western movies.) These films and TV shows (and books and comics) didn't just create a genre, they created an entire set of shared conventions, ideas that were so comfortable and familiar that they didn't need explaining to the average reader.
In Jonah Hex, this is a major element of the storytelling engine. The Old West isn't just a setting, it's an entire cast of characters in and of itself. You don't need a recurring cast when you can just bring in a Grizzled Prospector, a Noble But Savage Indian, or a Hellcat Widow With a Young Son and a Heart of Gold. Even Jonah himself, one of DC's finest creations, is something of a stock character (Grim Bounty Hunter Who's Secretly A Good Man).
This firmly-grounded setting and cast serves as a boon to a writer who's familiar with the tropes of the Old West, allowing them to generate stories quickly and easily. Jonah's profession always gives him a motivation to get into gunfights and trouble, and with so many characters, settings, and events to pull from, just finding new ways to combine them can lead to years of stories, even without introducing recurring characters or delving into the hero's backstory (although it should be noted that Hex did both.)
Interestingly enough, some years later Jonah Hex got another series, this one transporting him into a dystopian future. The setting was completely different (and some might claim a little too different, alienating some of his long-time fans who enjoyed the Western setting) but to the 1980s, a post-apocalyptic future with mutants and radiation was just as well-grounded and familiar as the Old West was a decade or so previous. In either case, the intent was the same--an intimately familiar setting took the place of a familiar cast, allowing the writer to use a rotating cast with all the benefits that a regular supporting crew gives to other characters.