While this is generally true, I distinctly remember from my childhood asking for and playing with Star Wars toys for the better part of a decade. (Yeah, there was an on-going franchise, but the toys sold for much, much longer than a year per episode.)
I wonder if there was something fundamentally different about that property or if there were just fewer options?
Marvel’s got a constant churn of content with their characters though. And not just movies, there’s the comics they started in, there’s kid’s books, video games, etc.
If people are still buying tons of Star Wars stuff, and mostly just Original Trilogy stuff, that’s a very different situation.
Star-wars is kindof an exceptional case. The original was the highest grossing film of all time when it was released. Return of the Jedi came out years before I was born but the toys were still popular when I was a kid, despite them having not made any movies recently.
Interestingly enough, they've pretty much stopped making any toys for the Star Wars sequel trilogy but are continuing to make original trilogy toys. Some franchises are just that much more ephemeral than others.
They can much longer when you merge classic move genre (dc comics, marvel, star wars) with timeless toys and utensils (lego&compatible, flashlights, balls, backpacks, pencils, lunchboxes). Lightsabers will sell now and in 2030 too.
Basically from 1978 (when they were released; they missed Christmas 1977 which was their goal) until they were discontinued in 1985 (a couple of years after the end of the original trilogy). While each movie added new figures and playsets, a fair number of figures were unchanged during the seven year period.
Movie releases used to be a lot more stretched out. Theatrical release, maybe a year passes then it hits the premium movie channels, another year and they get to make a big deal about it being aired on a regular network. Then finally a few months later you’re seeing ads for the big VHS release.
A blockbuster movie was like a 3-4 year marketing event.