Size constraints aboard typical traveler ships are caused by economics.
Tramp freighters, free traiders, and Subsidized merchants are all eaking out existances, becuase there is a surplus of individual ships to keep prices for travel down.
So these ships have to squeez every penny they can in operation costs, and maximize cargo and passenger loads to even break even. (the whole concept of subsidized service when the margins are so tight already for the existing ships can only mean that the goverment WANTS to drive prices down as far as they can go.)
By definition, a luxury linner is a luxury, and can ask virtually what ever price they want.
They are drawing from a much smaller clientle base, but those who are willing are almost uncomncerned about price and luxury is everything.
There would be fewer of these running, and you would liky wait months before a ship arrived that was going where you wanted to go, but to those who travel in those circles, they have the "luxury" to be able to plan ahead, and poorer people would have to scrimp and save FOR YEARS to afford a once in a lifetime trip, so they can set a date far into the futur and be ready when that day arrives.
So the economics would be VASTLY differnt. Your passengers are paying ABSOLUTE TOP DOLLAR and asking for EVERYTHING YOU CAN PROVIDE danm the price. Whereas a passenger on a free trader is barly pay the costs to move him one jump, on a luxury liner, every passenger is paying for all aminities, plus a quite hansom markup. so you can afford to just waste space. Casenos and shops with make several times in revenue compared to the same amonut of space warehousing people.
The casinos ill likly pay all the bills and a profit alone.
While there are certain shows in the vid palices, proection theaters, concerts and show rooms, that are incluuded in the ticket price, only the higest of the highend passages will get free vip access, and their ticket prices will be high enough to cover the lost revenue.
For all other passengers, the revues and basic classics would be in the price of the ticket, but all else is purely pay as you go.
Same with Food, probably three grades of food. Low end is still elegat compared to normal fare, most passengers would have access to 1 or maybe two meals a day in their ticket. the third meal would be either a contental style breakfast, or a brunch that you would pay for.
Second teir would be the highest range most people would be used to seeing. Formal dining with all the accuterments. Except for very high grade passengers, you would definatly pay for those meals.
Above that would be Almost a state dinner, as every one that could acually aford to get through the door would be qualified to arttend state dinners often as the guest of honor. There would only be a couple of hundred settings tops, if that many. The captans table and Snior officers would dine there, and virually no body would come in unless a vip passenger, or their personal guest.
Same with the shops. the main prominade would would have the highest end shops available on the most popular and comsmopalitan worlds.
There there would be a seperate deck of tryly Rodaio Dr class shops, and maybe shops that only have real estate in the luxury liner trade.
All of these spaces would generate several times the revenue per dton per jump than a free trader could earn total, in several years.