Several years ago when it was announced that Royal Caribbean had acquired the Celebrity Cruise Line, everyone was a bit concerned about whether the quality of Celebrity would drop. Being one of our favorite cruise lines and the one we "cut our teeth" on, we did notice changes. Thankfully the powers that be realized even though some of the changes were not that big, there were a lot of little things that loyal cruisers enjoyed. For instance, just the fact that there were molded portions of butter on the table rather than butter wrapped in foil.
I'm not sure how the corporate structure works but have you ever wondered who owns who in the huge cruising industry? Here are just a few examples of what I found.
Royal Caribbean has of course the Royal Caribbean line and also Celebrity Cruises, Azamara Club Cruises, Pullmantur (a Spanish line), and Croisieres de France (which appears to be a subsidiary of Pullmantur according to several sites I found).
Carnival, which is the largest cruise company, owns in addition to its Carnival Line, Holland America, Princess Cruises, Cunard Lines (which was originally connected with White Star back in the Titanic days), Costa, Seabourn (a very upscale line), P&O Cruises and P&O Australia, Aida Cruises (a German cruise line), and Ibero Cruceros (a Spanish line).
Third largest is Star Cruises, which I believe is now called the Genting Group and is located in Hong Kong. It owns 50% of Nowegian Cruise Lines.
I'm sure there are a lot more ins and outs to who owns who (or is that who owns whom?) but I don't have the resources or time to explore more. I just find it interesting that when someone asks, "What's your favorite cruise line?" the answer involves a much bigger picture.