You need to consider the means by which cruise lines have managed to attract so many more passengers year after year - while having kept the fare increases well below the inflation rate: they have cut expenses by cutting staff - while increasing passenger load, thereby reducing the share of fixed costs each passenger must cover, while reducing their “grocery bills” by cutting amounts and quality of food purchases.
Obviously, Carnival has followed this path, certainly NCL as well; but Princess, Royal Caribbean, HAL, and Cunard are essentially doing the same- perhaps at slightly slower rates.
You commented that “cruising used to be premium service”; you should realize that, if you want to receive premium service, you cannot expect to pay discount prices. Either pay for the premium spaces and restaurants on the same lines, or switch to premium lines. Anyone who started cruising 30 years ago (when cruising WAS a luxury) must remember the old days, recognize the changes and adjust his expectations.