Back to the OP's question, the reason that RCI did not start up in Europe the way that sister line TUI did, or Costa, is that RCI's ships are flagged in the Bahamas, and as such, they fall afoul of a very unpopular topic here on CC, cabotage (think of the US's PVSA). Since the cruises in Europe are all either cruises to nowhere, or cruises with ports all in one country (to date, Costa will soon start multi-country sailings), the EU restricts these cruises to ships flagged in EU member nations. TUI is all Maltese flag, Aida (tried to start) is German flag, and while Costa is Italian flag, it is the Italian international registry, and so had to get an exemption from Italy, but Italy granted it, since they still get the revenue from international registered ships.