That would be a great question to ask Gresham in an interview! I wonder if he had wanted the movies to kick off with The Magician's Nephew, but settled for LWW instead because the filmmakers felt that it was a better move in terms of cinematic appeal and name recognition? (I think they made the right choice, personally.)

I honestly don't know very much about the early days of development for the Narnia film series.

I have no clue either. :U But he does this intro thing for each book of the Focus on the Family radio drama, and he just sounds like a proponent of publication order through the way he introduces LWW. I think it's just bizarre, it's like he acknowledges that LWW is first by having it first in all these other media, but doesn't think it should be read first? Come on.

Actually, as far as the radio drama, I think I'm a derp. They're ordered chronologically in my download file, I've just been subconsciously listening to them in publication order lol.

I don't think it's such a big deal whether films of the Chronicles of Narnia appear in publication or chronological order. After all, publication order follows chronological order for the first four books, then there are two "flashback" stories - one to just before the last page of LWW, the other to the very beginning of Narnia - and then chronological order is resumed in Book 7 from shortly after where Book 4 left off. The way the books are written, it suggests reading them in the order they were published as the narrator goes to some lengths in LWW to introduce Narnia and Aslan, while in HHB and MN he assumes the reader knows about them already; but when adapting the stories into films, they could be treated slightly differently so that a film of MN, say, could make more of introducing the idea of Narnia to the audience. On the other hand, many successful film and TV series have "flashback" episodes that provide backstory, and then normal chronology is resumed in subsequent episodes. I think the main reason that LWW is done first is because for many people, LWW is the only Narnia story they've ever heard of.