There are a lot of older people who go on cruises who would not go if exposure to unvaccinated cruisers was involved. Perhaps we need COVID cruises and VACCINATED cruises. I would guess it would be more difficult to recruit employees to work on the COVID cruises.
Cruise lines would probably have to pay the employees more, charge more, and expect to be turned away at ports for COVID cruises when infections break-out.
Maybe things will change now that Omicron has moved through, but I suspect the elderly will in general be more hesitant to cruise. And since they often pay for their extended families to cruise with them, there will be fewer cruisers. We are in a bad place, but maybe it will improve.