Perhaps the western will always enjoy resurgences. Western comics usually depict a protagonist who bears the character traits of all good protagonists in every genre: fearlessness, selflessness, resourcefulness.
While Matt Hawk is the chronological inspiration for one superhero at least, the supervillain prototypes are over in Kid Colt: The Raven, The Fat Man (and his bewitched boomerang!), Iron Mask. I would contend there's something of the superhero in Lady Rawhide as well.
Horror may not be a naturalistic fit for tales of the western plains but there were certainly western horror tales.
You have to wonder though with curiosities like the space western, whether they can be combined. They've sent Hex into space and yes pitted him against the supernatural. Stories in his natural setting are the best and, really, the best you can get in a memorable western. Little period details are recalled and cults and cultures that were dominant then make an appearance. Genuine villains can be envisioned from the conditions of the time, just as their victims can.
I am not the greatest western fan but I'd prefer to read these exploits before the more fantastic tales any day.
Is the furthest you can ride into the sunset as far as the original Ghost Rider, with all the appearance of a spectral horseman but not really a spook, or part of a milieu where such things existed? While farfetched that someone would wear such a get-up, does that really make it fantasy?
If you look at some sites, the definition of 'western' is broader than just your 'cowboys and indians' and can include the Revolutionary War or War of Independance.
It is another genre where action and adventure are part of it. Romance in the West might be about something else but, again, drama is natural and ever present.
What divides the comic book depiction of past exploits into Western and other (such as sword & sorcery, historical fantasy)? Is it the use of guns vs bow and arrow and guns vs other guns? Is it American History (X) - events leading up to the close of the nineteenth century and divorce from the dusty plain; feted to continue only in Buffalo Bill's revue and racy paperbacks?
We rarely see the work of the detectives of the day so Pinkerton agent, Caleb Hammer's one appearance was particularly welcome; especially since it was a good story and good artwork.
And besides making good heroes, cowboys are also funny.