Personally I like the 10 for 75 card that RCCL sometimes offer which is similar to the Martini deal they used to offer in skyline lounge, not sure if they still do and nothing like it on the classics.
The packages themselves are a waste, but I am guessing lines hope people buy them and then expect them not to come close in actually getting their value out of them. One of those purchases that sounds good till you actually look at it. Seeing how some people prepare to cruise at work I could see many paying for it without figuring out if it is a good or bad deal.
I'm sure you are right. Most lines make their money off the people who buy the package without even thinking about if it is a good or bad deal for them.
But like anything, there is a subset of extreme planners (sound familiar?) who do break it down. I have been on the boards for other cruise lines, and not only have they broken it down by "How many drinks per day makes it worth it?" but their spreadsheets (sound familiar again?) even distinguish between TYPES of drinks so X beer, or Y wine, or Z mixed drinks, per day, etc. They also account for specialty coffee drinks and things if those are included in the drink plans.
So if one goes and finds one of those spreadsheets, one can easily put in their normal habits (wine with dinner, a couple mixed drinks later, specialty coffee in the morning and at lunch, etc.) and figure out if it works for you.
Where the cruise lines REALLY get you is that most of those packages are required to be purchased for every over 21 adult in the stateroom. Ostensibly it is because otherwise sharing drinks would be too easy (which is valid) but realistically, it is because there is almost never a stateroom where everyone drinks enough to make it worth it.
Though there are plenty of posts by people who manange to MAKE it worth it. Which, to me is the best reason for
DCL not to have such a package offering.
I do like the Skyline Passport option though! My wife and I split it and it was nice.