(or "Guest Starring: The Pet Rock!")
The first thing to note, when we discuss the 'Essential Marvel Horror', is that it's not just a random collection of Marvel comics that told horror stories. It is, in fact, a collection of the appearances of the Son of Satan, who had his own comic book for several issues, and of his sister Satana, who made several appearances in a variety of different comics (but never got her own series, sad to say.) The climate of comics has changed to the point where putting out the 'Essential Son of Satan' just doesn't fly.
Which is, in fact, the point of today's storytelling engine: The pop-culture comic. Because 'Son of Satan' was, in fact, an attempt by Marvel to cash in on a popular trend. At the time it was released, the film 'The Exorcist' had just made supernatural horror, specifically stories about Satanism and demonic possession, not just acceptable but downright popular in all sorts of media. 'Ghost Rider', which we've examined already and in which Daimon Hellstrom, the Son of Satan, made his first appearance, was another attempt to cash in on the Satanism trend, combining it with the fad for stunt-riding as well. (Daimon's name is a none-too-subtle nod to another popular Satan-flick of the day.)
The idea of a pop-culture comic is simple enough; take a current popular trend, combine it with the traditional storytelling engine of "person gets super-powers, becomes super-hero, and tries to help people", and sell it until the trend dies off and the comic's sales plummet. Then cancel. Find new trend, and repeat. Marvel's 70s comics seemed particularly vulnerable to the pop-culture comic, although this wasn't so much because of anything at Marvel as it was that the 70s were a great decade for fads. (The 70s at Marvel gave us Ghost Rider, the Rocket Racer, the Son of Satan, the Disco Dazzler, and 'Howard the Duck for President' buttons, just to name a few. Sadly, we never got a streaking superhero.) Certainly, if you look back to the 60s, you can find similar trend-based comics; 'Brother Power, the Geek' is fondly remembered as a bizarre hippie-themed series, albeit one that didn't last long. It gets harder to spot faddish comics as you approach the present, just because it's harder to tell what's going to have staying power and what isn't, but Night Thrasher, the extreme skate-boarding vigilante, looks to have been a fad in action.
So are these storytelling engines doomed to the junkpile of pop-culture ephemera? Can a storytelling engine based on a momentary trend gain more staying power? In general, I'm inclined to say no. Occasionally, the writer can "decouple" the character from the trend, reworking the storytelling engine into one that doesn't depend on the fad for its popularity. (Ghost Rider counts as a success, Dazzler has to be considered a failure in that regard.) The Son of Satan obviously has a few fans; he's had a mini-series or two over the years, and the very release of the Essential collection shows that he's not totally without legs. (Then again, supernatural horror isn't as overtly 70s as disco or C.B. radio...anyone remember "U.S. 1"?) But as a character so linked to a particular trend, he's probably got to bide his time between appearances, waiting for the audience to be in the mood for him.