Apparently not even Carnival. This subject has been on the docket for over 10 years. They brought in an outsider who was known for loyalty programs for a major hotel chain. After several years and much effort, they abandoned the project. No idea why, but the obvious reason would be complexity of any future program and grandfathering existing levels in. Things like changing to money spent vs just days, and bonus for cabin types like suites, and difference in cabins purchased vs discounted comps for Ultra and Elite and on and on and on.
My personal thoughts are is that it HAS to change as before long the vast majority of the majority of ship will be plat and diamond. Even at 400 days, I do not see them giving free drinks or anything like that. Of course there a ton of options they COULD do, but I will believe it when it is announced.