I think fancy resorts are similar to fancy desserts: that first bite may be the best thing you've ever tasted, but if you make a meal out of only that, you're going to start feeling nauseated sooner rather than later.
For me, cruises/all-inclusives don't tend to make me happy, because I like a variety, period. Keeping on the food theme, yes, I love having a wonderful, special meal at an expensive restaurant. But I also love the taco cart down the street, which makes some pretty freaking awesome tacos for like $7. A steady diet of fancy meals is still just doing the same thing over and over. (Not to mention that I've never had a single resort/cruise meal that was anwhere near the quality of a great non-resort restaurant -- they're usually monotonous and mediocre. And the one thing I do not appreciate is mediocre -- particularly when it comes with a hefty price tag).
Maybe for that same reason I don't tend to really click with other guests at these places. I mean, yeah socially awkward introvert, so it's not like I'm making fast friends everywhere I go. ;-) But our vacation choices do reflect at least some of our values/priorities, so I think when I'm at one of those fancy places, I probably don't share the same values/priorities as someone who sees that as the most amazing vacation option ever (I mean, really, a Mustachian and a jet-setter aren't really going to have much in common to bond over, will they?). Conversely, when we travel on our own, we meet a number of people, some of whom became friends for years -- probably because we both share the same interest in whatever little geeky thing we chose to do that day.