I have a hard time understanding why a cruise line wouldn't say, "Our guests find great value in our cruises and especially like the all inclusiveness of things like tours and drinks so they know what their total cost will be before they set foot on our ships. The proof is that we are sailing full and X% are repeaters."
Possibly the line would want to drop the "X% are repeaters" if the number is declining, but otherwise my questions really go to why would you say, "Heck, we are making more off of each guest than we ever have".
As for the quality of the tours, I can tell you that some tours are raved about, other are not. Some of that is a function of the business...as the cruise lines are very much dependent on the tour operators and what is actually available in any port. However, there are also an increasing number of complaints that (a) the tours are disorganized and crowded; (b) people are being frustrated by not getting the "free" tours they want due to others taking multiple tours; and (c) the "good" tours (and ones which would have been $200 or less) are now extra cost. I can't tell you how much of that is just sour grapes versus legitimate versus luxury cruisers finding a less than luxury experience.