The other things priced into the "experience" are why I call out cruises separately. With a hotel, I get it, a room is a room. But a solo cruiser is eating half the food, drinking half the drinks, taking up half as many seats at shows...

Maybe that's the problem. Cruises rely on people spending a lot of extra money onboard the ship, or drink packages, nicer dinners, excursions, etc... fewer people doing that, with less social pressure to spend extra, means less money for them and they have to make it up somewhere.