Disney Cruise Lines fill a niche market. Not many people are willing to pay twice as much on average for lesser itineraries, product, service just to cruise with a rodent. (Yes, yes, I know, people are inhaling pixie dust and putting logic aside)

I do wonder if with four ships they now find that they have exceeded demand for such a specific product? Being such a small player in the market, they don't have the ability to create a variety of unique itineraries, which also seems to be an issue for many who would do a repeat cruise with Disney, if only the itinerary were different.