My opinion is it's all a training issue. With the number of ships that are being cranked out I don't believe they properly train the crew anymore. The pursers desk people aren't in the tipping pool and they have to be some of the snottiest unhelpful people around. Maybe since they aren't working for tips they don't feel they have to be nice.
If Carnival spent as much time training the waitstaff to take care of the diners needs as they do teaching the song and dance numbers....
That being said, I've never had a bad waiter or room steward just some that were better than others.