Disagree - lots not needed.
MANY people cruise other lines and never step foot in the casino, myself included. There is no need for casinos.
They could offer drink packages, I've bought on half my cruises but haven't on half my cruises. Each person does the math. The nice part about those packages is they include fresh squeezed juice, smoothies, specialty coffees, bottled water .... not all involves alcohol but would have appeal. BUT they don't have to offer the packages, I remember the day they didn't exist.
DCL would do just fine without them. Disney adults already pay crazy prices to drink in parks.
Disney already has a long list of alcohol tasting events on DCL. They already have lounges and nightclubs and they could expand the 21 and up requirement easily. They could expand an adult non-alcoholic menu as there are plenty of adults who don't drink.
Disney already has adult only pools, relaxation area and spa.
Disney already has plenty of areas designed for adults such as bars, lounges, nightclubs that they could limit to adults during particular hours.
Disney has been advertising their cruises to families, and they are apparently loved by many. But there is no reason they couldn't amp up the adult only areas, the adult entertainment say 10 pm on and market to the Disney adults. There are plenty who likely haven't looked because they have been made to believe by others they are only for younger families. My DH is one who was told it was about character meets and character meals, nonstop Disney in your face.
Disney's whole organization, marketing, product structure is changing under the new leadership - who clearly is income focused, no matter what the impact to the individual consumer.
DCL has a real opportunity to pull in a large market in this country which can make up for losing some international customers and those who won't vaccinate their kids. And honestly their ships would only need change ups of their offerings in their already existing hard structure. Cost would be acceptable for the potential of a whole new big target market, with money to spend.
I get the younger families might not like this idea, but as we see with all things Disney ... what will generate the most income with the lowest investment is what they like, AND this is one I think could work out well - fill ships.