I find humor in that excuse for two reasons. One, Disney moved the film to that date on purpose, away from its originally planned date of December 2007. The fact that Walden Media, which co-produced Prince Caspian, also had a Christmas movie, The Water Horse, may have been a factor in the move, with Disney not wanting to cannibalize its own audience. But the Narnia series, with its PG rating (though undeserved) and overt Christian allegories and occasional cameos by medieval-weapon-distributing Santa Clauses, is a much better fit for December than May. Any fool can see that.
The second reason the excuse is amusing is that it's not like the competitiveness of May 16 was a huge surprise. It's not like they moved the film to May 16 at a time when there were no other major titles announced for around the same time. It's MAY, dummies. That's when big movies come out. Disney knew that Iron Man would come out on May 2 and Speed Racer on May 9, and they moved Prince Caspian to May 16 anyway.
Which brings us to another point: Speed Racer flopped. So when Iger says that May 16 was too competitive, what he really means is, Iron Man was too much competition.
So what do you think? Was the marketplace too competitive for Prince Caspian? Or are there other reasons for the film's disappointing box office?