You are doing a lot of assuming. You could sit here all day and come up with 100,000 plus scenarios of comparing land vacations to cruise vacations. Using your scenario of a mountain vacation someone else could come up with quite higher figures. IE: We'll call them Couple #1 and Couple #2.
Couple #1 rented a 1 bedroom value condo, they drove from Kentucky to the mountains in Tennessee, they ate out at value buffets, value restaurants like Denny's and Shoney's. Their entertainment was a movie, playing miniature golf, go-karts, and the Ripley's Believe it or Not.
Couple #2 rented a 1 bedroom deluxe condo, they drove from Michigan to Tennessee, they ate out at finer restaurants like Greenbrier, Alamo, The Fox and Parrot Tavern. Their entertainment was going to Dollywood, Dixie Stampede, a comedy show, and a murder mystery.
Which couple spent more money? As I said we could come up with thousands of scenarios both land and cruise vacation. Let's not split hairs. The point I was trying to make in my previous post is that basic cruise fares are too low. The cruise lines try to make it up with on board purchases. People will try to skirt around those on board cost, so the cruise lines look at more ways to generate revenue. The result is more nickel and diming, added surcharges and making cuts. It's a vicious cycle. One that could eventually lead to charging ala carte for meals. Then you will be paying that same base fare plus your meals, which at one time were included in that base fare.