I have to respectfully disagree with 'txncruiser'. We would LOVE to have a 7 day cruise to nowhere. I know this is weird, but we really like being on the ship and don't care a whole lot about the destination it may be sailing to. For us, the ship is our destination.
I think the cruise industry's best bet is to disperse it's ships to more varied ports and come up with new and unique itineraries. By doing this, the cruise lines would be building a clientele base of new cruisers. When the right time comes for the cruise ships to be sent back to their normal itineraries, they will have increased their potential passenger base. By then, maybe many of these people will be so enthralled with cruising that they will be willing to fly anywhere to cruise.