I am a young marketing executive my self in my 30s and my philosophy as is with many of my colleagues is that the only reason young people don't fill the ships is because they don't want to cruise with old folks, on a boring boat. But as marketers our job is to completely re-emagine the market and define new expectations of what a "cruise is".
To do it effectively we need to basically start fresh and clean to attract the masses to so that effectively older people, seniors and anyone not fitting the new image needs to be phased out so the marketers can do their job and get young people to fall in love with the concept of cruising.
Yes it will take years to convert the industry but a massive change is needed to save the industry, the seniors will have to find another way to travel and other ways to vacation because cruising is going young hard. Just my insider take based on all the new advertisement assets cruise lines are focusing on, they are smart to do so.