I was asked about this one a loooong time ago (we're talking almost two years, heck, maybe LONGER), by, I believe, commenter suedenim, about Marvel's late-70s comic series starring Toho Productions' famous movie monster, Godzilla.
The series began in 1977, and ended fairly shortly after, in 1979, after only two years of comics.
Sue had heard that the reason Marvel ceased publication of the title was because Toho had problems with the way Marvel had depicted Godzilla in the comic, but after broaching the topic with the editor of Godzilla, Jim Shooter, the reason appeared to be a typical refrain for licensed comics.
The same problem that led to the ending of Star Wars, Transformers and GI Joe - sales.
I asked Shooter, "Did Toho back out of the Godzilla series because of problems over how Godzilla was depicted in the comic?" and he replied
No. It wasn't selling, so when the license ran out, we didn't renew.
Reader Daniel wrote in the comments section an interesting further elaboration via Michael Eury's awesome comic magazine, BACK ISSUE! -
Actually, BACK ISSUE! covered Marvel's GODZILLA in some detail. Marvel had an initial license with Toho for 12 issues, after which they would have to go through the licensing process again. They paid a tidy sum to use Godzilla, but every time they asked about using Rodan or Mothra or any of Toho's other creatures for a single issue story, Toho informed Marvel that they would have to pay another licensing fee for that chracter that would be the equivalent of what Marvel was already paying for using Godzilla for 12 issues! So, they came up with their own monsters for Godzilla to duke it out with.
Since it had been selling reasonably well, they went back to Toho to re-license Godzilla for a further dozen issues, only to find that Toho jacked up the fee. Although the series continued to sell at the same numbers, Marvel was now making less profit. So, as they headed towards #24, they planned on wrapping up the storylines, just in case. Sure enough, when Marvel went back to Toho, the movie studio wanted to charge an even higher licensing fee. Since this would have guaranteed that Marvel would be producing the comic at a loss, Marvel decided to drop it.
So there ya go, when Shooter says "It wasn't selling, so when the license ran out, we didn't renew," he was meaning what Daniel explains in his comments - it wasn't selling enough to pay for the licensing costs.
Thanks to suedenim for the suggestion, and thanks to Jim Shooter and Daniel (and BACK ISSUE!) for the answer!
Okay, that's it for this week!
Feel free (heck, I implore you!) to write in with your suggestions for future installments! My e-mail address is firstname.lastname@example.org.
See you next week!