This is an interesting question. Generally speaking all companies have a similar organizational structure. In light of this, I would say that Carnival, which has many moderately priced cruises would be run in a similar way as a more boutique / wealthy cruise line. There will be a CEO, executive body of board members, a CFO, directors and so forth.
The difference will be in customer satisfaction and amenities. As you can imagine the cruise companies that deal with the more wealthy clients will treat customers in a way that they are used to be being treated. It is not a nice thing to say, but money makes a difference.
The only possible difference that I can think of is that wealthy clients will have more of a rapport with people who are higher up in the cruise line leadership. This make sense. If you are dealing with customers who are CEOs as well, then it makes sense that they would have a relationship with the leaders of the boutique /wealthy cruise line.