How about this point? You're deliberately confusing a bit of color text with ship design rules.
Do you seriously think the author even once thought about life support capacity when writing up his little intro? It's fluff and nothing more. It was meant to set the mood for the players. They're recently demobbed soldiers who hitched a ride to Emerald just like the sailor, soldier, and bombardier hitched a ride to Boone City aboard a B-17 The Best Years of Our Lives. It's a plot device, like a Shakespearean shipwreck, meant only to get the characters to the stage where they'll perform.
Context counts and you're ignoring it.
So does consistency. If I'm watching a series in which, for plot reasons, it is possible to do X one week, but in following weeks it becomes impossible to do the same thing without some adequate explanation for the deviation, then the series isn't worth the watching. Not that a lot of television hasn't fallen into that trap, but it's pretty lame when it happens.
Plot device or not, it is presented as possible in one canon source, and not just some tangential source - it's a GDW-published adventure. I've not heard anyone talking about that particular source being decanonized, ergo it is one possible arrow in the quiver of the game master - a very restricted arrow, perhaps, but available nonetheless. Think you're going to advertise for riders in your cargo hold? Not if the starport authorities or customs officials have anything to say about it. On the other hand, if the player can manage to get around that little barrier and can find people desperate enough to take such miserable passage, or when the meteor is coming and you're their only hope, guess what arrow the gamemaster has available in his quiver,
should he choose to use it.
I think the thing you're ignoring is that you're free to discount whatever canon elements you don't like, and he's free to embrace whatever canon elements he likes, and you're both absolutely right within the context of your own TU's. No harm, no foul - and others are entitled to hear both views.
Yes, I'm as much a fan of realism as anyone else, but arguing about the life support capacity of a far-future starship, in a game where ships put out as much power as small cities and yet can somehow manage to be difficult to detect, might be a bit much. The great thing about plot devices is, it's available for other storytellers too.
It might be easier to accept it and try to resolve the contradiction. Consider the situation of our soldiers en route to Emerald. We know they can breathe, that much is a given. Beyond that, anything that gets them there alive while making the alternative less attractive and therefore less viable is fair game. No food is provided - they have to bring their own. Let's also say, since we want this to be something people don't really want to do: no access to the freshers - the recycling system isn't able to handle the added load of solid and liquid wastes.
Yes, unless you invest in some port-a-potties, it's buckets for you, and maybe a few barrels or something else in some out-of-the-way corner of the cargo bay to dump the waste in. We can airlock it if you bring enough containers with good seals to do the job - otherwise it stays down there with you, 'cause I'm not having that sewage flash-boiling in the airlock and getting all over everything in there. And then there's water - if the system can't handle your waste, then I can't afford to be giving you water out of the ship's stores, so very likely you bring your own of that too.
Climate control? Well, there's air circulating, or they'd have died. That doesn't make it comfortable. No idea what kind of ship that was, or how big a bay is, but twenty warm bodies to a compartment can get things pretty warm pretty quick if the ship's adequately insulated.
Did I mention "dull"? Seven days with nothing to do but whatever you brought with you, and nowhere to go.
What are you left with? You're left with seven days in a hot, increasingly stinky compartment eating and drinking only what you brought with you, no showers or baths, the warm air rich with the ripe aroma of the 19 other unwashed people sharing your bay, peeing and pooping into buckets and then dumping that into a container that you close as quick as you can to keep as much of the stink as possible from escaping, no fresh-air deck to escape to as they had in the Age of Sail. All in all a mode of passenger transport that might be acceptable to refugees fleeing likely death or to soldiers fresh from war and inured to hardship and discomfort, and to precious few others.
Maybe some enterprising soul could think up ways around some of the hardships, but precious few captains are going to be willing to put passengers in with their cargo unless they're sure they can keep the cargo safe. If - as many of us do - you're running in a TU where cold sleep is not the Russian-Roulette game that the Classic rules make it, then there's only so much one can spend reducing hardships before it begins to make more sense for the folk to buy a low passage.
If you
are running a risky-cold-sleep universe, then it still comes down to the right combination of desperate passengers and captains who lack cargo for the trip. In most instances, the need to give a tolerable journey while securing your cargo favors some version of the "transport pod" idea the OP is presenting. I really don't see this as a game-changer.