I would not read too much into DCL offering promotions. That does not necessarily mean they are stuggling. It might only mean the difference in a 7.1% profit margin to a 7.4% profit margin.
I found this little factoid: In 2008, about 35.7 million families (46%) had children under 18 at home
So if at any given time in the US 45% pf households included children, I'm thinking the 'market' for FAMILY vacations is pretty constant.
Every year xx million new families have children at that 'perfect age' to take a
Disney cruise so there will always be a constant 'supply' of new, first-time cruisers.
Additionally, my children are now 18 and 21 and soon they will have families of their own...and I can gaurentee you that a DCL family cruise will be high on their list of family vacations. I can also gaurentee you they would NEVER take their family's first cruise on anything other than DCL. They grew up with Disney and they love Disney and their families will likely be lifttime DCL cruisers!
And
that is why DCL will continue to grow and eventually dominate the family cruise market.