The entire travel industry (airlines, cruises, hotels, car rentals) are taking a severe hit getting back to staffing levels pre-pandemic. It's a function of survival of the fittest, however. Employers who treated their staff well before and during the pandemic will have more people willing to come back. Paying people more, giving them more perks and benefits, and improving working conditions goes a long way. What we will end up seeing is fewer and fuller ships (and planes, cars, and hotels), and more expensive sailings (and flights, hotels and car rentals) and poorer service until this all balances itself out in a few years and new recruits appear.
As passengers, we will need to take all of this with a very large dose of patience.