They really just lack any good place in the game, even with luxury cabins for the simple reason that general passenger missions suck in terms of payment outside of a select few (most of which are either not worth money/time spent or are like robigo and just fast enough that shit credits add up fast).
There are roughly 3 good routes i know of in the game (probably others but most people dont share moneyprinter systems for fear of developer nerfs) for passenger missions, and in every single one passenger ships are basically deleted by normal ships.
Unless Fdev greatly boosts payouts from luxury class ships so you get a major bonus for the "luxury" of the ship, they really just have no place in the game beyond meme pirate builds, showing off wealth, and clogging up the exit to Jameson memorial.
