First, I would like to say that I don't assume to have any remnants of a brain left recently but:
I've thought about this and while we took a transatlantic repositioning cruise this year and loved it, we probably would never do it again. I would be concerned that there is not sufficient volume of demand for such a product.
While it was the state of the art years ago, today travellers have no patience for multiple day travel to a destination. The cruise has to be the destination. I believe that cruising will remain healthy though the new ship schedule may require a bit of tweaking.