Hear is what I see with the ships getting bigger in a bad economy. Supply with outweigh demand and the prices will go down in order to fill the ship and increase demand. I have seen this in the Mexican Rivera cruise. Mariner of the seas and Carnival Splendor are the biggest ship ever to cruise the route. All of the sudden supply increased quite a bit. Demand decreased or stayed the same my cruise price went way down from the past cruises.
I agree with Dayvid a great way to increase demand is to offer more ports. For the Mexican Riveria there are a lot of Sea of Cortez ports the cruiselines could add instead of just doing Cabo, Puerto Vallarta, and Mazatlan.