How about if they could start cruising again if the passengers present proof of vaccination? And then after a couple of years, drop that proof requirement if COVID fades away.
They may start of that way, but it will leave a lot of past cruisers ashore, because some of the cruisers won't get vaccinations, and other cruisers want to spend money on a cruise to have a good time without restrictions onboard or ashore, but don't want to feel like they are paying to be part of a medical experiment.
IMHO it is taking the big 3 Cruise lines too long now to recover, and they are going to have to decrease the number of ships in their fleets, and adjust their itineraries to survive. And creditors are now involved with Billions of loaned dollars to the Cruise Lines, and will have a say in the comeback. -Tom