Just because there is a big liner going doesn't mean you can't find people going smaller. And vice versa. You can get a 707 or 727, even a 757 into Kenai.
It depends a lot on whether a starship is running a regular route, or wandering, I figure. And whether the vessel is hitting High-Pop and High-Tech worlds.
It is hard to fill a dozen staterooms with High Passengers on a
regular basis if you are relying on Free Trading in the hinterlands.
The basic J-1, 100-dton starship (with a crew of 1 pilot and 2 stewards already figured in) will have around 50dt of payload space, which translates into perhaps 12 passenger staterooms. A ship that is filling all of those with High Passengers every fortnight will be leaving money on the tarmac, however -- it would be more profitable to build a larger ship and not ignore all the associated Middle and Low Passengers that will accompany large numbers of High Passengers when rolling randomly for availability.
Bearing in mind that each Steward typically costs the ship
at least KCr15/month in revenue by displacing a potential Middle Passenger, while Middle and Low Passengers themselves are much more profitable than freight, I claim that you can really never have too many passengers in Second or Third Class. Otherwise, exclusively-High-Passage ships are going to have to be prepared to have slow weeks and months on occasion.
But there are probably more people with ample disposable income jaunting around modern-day Alaska than between any hypothetical pair of POP-6, TL-7 worlds, I would think.
For the ship in question, I would typically lose the second Steward by default and thereby indirectly cap High Passage slots at 8, leaving the rest of the non-crew staterooms available for Middle Passage, as well as adding in half a dozen dtons of Low Berths to make sure to grab that easy money as well. That way, the ship can
still maximize its revenue for any situation when fewer than 8 High Passengers are aboard.