In 2005, I never expected the interest in the series would so completely evaporate.
I think
Narnia was always going to be a problematic film series.
If film audiences want "more of the same,"
Caspian was always going to be a hard sell as a sequel to
Lion.
Caspian, the book, essentially reboots the entire
Narnia concept; the major players (outside the Pevensies) are all different, the names and places are all different.
Lion and
Caspian might as well be set in two entirely different worlds because there's so little continuity between them. It's to the credit of the screenwriters that they tried to pull more of
Lion into
Caspian than Lewis did, but they were plastering over the cracks in what is, arguably, the weakest of the Chronicles.
(I've never spent the time researching the creation of the
Narnia series the way I have researching Middle-Earth, but I've often thought that
Caspian might have been a separate story that Lewis decided to add the Pevensies to, perhaps because his publisher wanted a sequel to
Lion.)
I also think that, frankly, Walden Media got
very lucky with
Lion and that the film vastly over-performed. Studios circa 2002/2003 were looking for the next
Lord of the Rings, and Walden just happened to hit with
Lion when that iron was still mildly warm. By the time Fox released
Eragon in 2006 and New Line released
The Golden Compass in 2007, the iron wouldn't even pass for lukewarm. I think that what the studios didn't realize is that
Lord of the Rings and
Harry Potter had loud, passionate fanbases, something these other series wannabes that followed in
LotR's wake simply
don't have. Best-selling novels? Yes. Cultural touchstones? No. Just because it
looks superficially like
Lord of the Rings doesn't mean that audiences are going to
respond to it like
Lord of the Rings. (And yes, I recognize that some novelists, like Dennis L. McKiernan and Terry Brooks, have made entire careers of writing
Lord of the Rings-without-the-serial-numbers fantasy, but films and books are two entirely different beasts.)
Narnia provides a comparatively weak source material to start with, and that was going to lead to diminishing returns no matter how well the first film did. I don't even think an aggressive release schedule would have helped. Maybe
Dawn Treader will find its legs and the series can limp on to a fourth film. But that's just it.
Narnia is a
limping series.
Contrary to what most people think, Lewis didn't actually write the Narnia novels to be deliberately viewed as an allegory for his adopted Christian beliefs, instead stating that they were meant to be fairy tales first and allegories second.
Unfortunately, Liam Neeson stepped into that pile of doo when he
angered Narnia fans by suggesting that Aslan can represent any spiritual or religious figure, like Muhammad or Buddha. The
Telegraph writes: "Walter Hooper, Lewis’s former secretary and a trustee of his estate, said that the author would have been angered by Neeson’s comments."