KYCruiseCrazy -- What you're saying is partially true: If Disney had one more ship right now, they'd most likely be able to fill it at the current prices during "peak months". However, right now the ships aren't quite full during the off season -- it wasn't full when we cruised in November, and I think that's not uncommon.
Soooo if they had three ships, they'd have more empty rooms during the off season. Yes, a new ship would attract some new business, but not 1/3 more business than they have now. They'd end up discounting more cruises, which would be good for us, bad for the company.
Right now they can charge more than the other cruise lines because we're willing to pay it. It's supply and demand. The supply of rooms is limited, so they can demand the prices they want. If the supply of rooms goes up, they'll either have to increase their number of customers (where would they come from?) or decrease the cruise cost to fill their rooms.
While we're talking about filling the cruise ships . . . as a Disney stock holder, I think the Land and Sea package was a brilliant idea. Disney World parks already have all the business they can handle, and offering the L&S package made people who otherwise would never have considered a cruise say, "Well, maybe we should . . . after all, it's Disney." This package DID make more customers appear. Do they have another such trick up their sleeves? If they launch a new ship, they'd better!