All companies are interested in maximising profits but to say -
A couple or individual that have an interior cabin, don't drink, don't use the speciality restaurants, don't go on P&O excursions etc are of no interest whatsoever to P&O, or indeed, to any cruise line.
Is a complete and utter nonsense with no foundation whatsoever. You have not spoken to everyone on P&O ships who cruise and ask if they drink, book speciality restaurants or go on excursions so to say such a statement without any knowledge of such is fanciful. How do you know that those sitting at the next table in a bar or speciality restaurants are in an inside cabin or higher. So to make such a statement is rather silly.