...Except that I question that the life support a standard mid or high passenger gets on standard passenger liners is anywhere near the bottom limit. And any passenger who boards a free trader expecting the average standard service is kidding himself. ...
Missed the point on that. The point is, if you're faced with a choice between paying, say, Cr3000 to be crowded in like sardines and smelling dirty feet, or paying Cr1000 to go to sleep here and wake up there, you would be an utter fool to buy the Cr3000 ticket unless there was some serious downside to the Cr1000 ticket. Either the Cr1000 ticket MUST come with a serious downside, or the higher-price passage MUST offer sufficient amenities to entice you to pay the higher fee - even if it's a tramp liner.
We can argue down the base cost. Timerover pointed out the JTAS article with the Cr50,000 shelter that provides life support for 100 days for 8 people. That's an averaged cost of Cr62.5 per person-day for the whole shebang, walls, power plant and all. It's hard to justify a Cr2000 per person per trip charge for expendables (and I understood it to be Cr2000 for the trip with the assumption that you were spending the next week in port or otherwise not dependent on ship's life support.) when you can spend less than that for an entire system
with power plant and structure.
However, the bottom line will remain that the merchant can earn
a minimum Cr1000 per ton for cargo. Whatever he gets from passengers has to equal or exceed that or it's not profitable to take passengers. BUT, whatever he offers passengers for their money has to offer enough amenities that it's worthwhile to take that instead of low passage.
Yes, people will put up with one heck of a lot of misery to get from point A to point B, but nobody nowadays goes to California by Conestoga wagon when they can take a plane, drive their car, hop a train, or buy a bus ticket and thereby enjoy at least some air conditioning along the way.