On our most recent cruise, we walked through the casino as necessary to get to other places; we never visited "on purpose" (though I find that very carefully built environment a fascinating study in people and psychology and worth a visit for that alone). We rarely attend the shows. A good jazz trio or pianist such will get my attention but the revues and cruise ship versions of game shows or talent shows don't interest me at all. Instead we visit the ship's library or go to the club at the back of the ship (that requires three elevator rides) and we read or just watch the scenery go by.
For us, the value of a cruise is unpacking once in a guaranteed hotel room, not having to figure out much in the way of meals and transportation if we don't want to, and having destinations that change. But, yeah, after seven or eight days of cruising, I'm done with the atmosphere. I know some people live for the communal celebration; I'm not one of them. So far cruises are still worth the money to us, but I can travel just as well without the boat -- for me, it's a conveyance. The enjoyment of cruising, it seems, is on a spectrum.