We should also note that King has only published one novel as “Richard Bachman” since the secret came out.
Here’s the timeline:
Rage was published in 1977
The Long Walk in 1979
Roadwork in 1981
The Running Man in 1982;
all of those were paperback orginals for Signet. Clearly, this wasn’t a “marketing gimmick” at this point; the money he made for those books was miniscule compared to the money he could have gotten for selling them to Doubleday, his hardcover house at the time. In fact, the first two were “trunk novels,” written before Carrie, and the other two were also relatively minor work.
Thinner was published as a hardcover in 1984, and the added attention paid to it ended up blowing the pseudonym. (IIRC, King never denied being Bachman at all; once the question arose, he immediately admitted to it.)
Since then, King has published exactly one novel as Bachman: The Regulators, in 1996. Even that was a special case, since it was published at the same time as the “Stephen King” novel Desperation, with a complimentary cover and a shared marketing plan. The two novels also tell similar stories, or, more specifically, tell related stories in different kinds of fictional worlds. “Bachman” became an excuse or reason to tell a story two different ways.
The Desperation/The Regulators diptych might be seen as a “marketing gimmick,” but I seem to remember that King called his publisher and asked if they wanted to publish the books that way (i.e., it was his idea to begin with, and he did it for creative, not marketing, reasons).
Similarly (and off-topic, but I’m making a point here), The Green Mile didn’t come about because Viking Penguin (as was) said, “You know, we’d really like to have six King paperbacks take over the whole bestseller list for most of a year.” It was King who wondered, “Could I write a serial novel on deadline like the great Victorians?”
Whether or not you like his work (and I haven’t kept up with his books in recent years), you have to admire Stephen King as a writer who takes risks with his books – he genuinely seems to be more interested in telling the stories he has to tell than in fitting some audience’s image of him.
…but when you get blue, and you’ve lost all your dreams, there’s nothing like a campfire and a can of beans!