Or a reflection that Vargr and non-Solomani Humaniti have the same need for personal space. It's easier to cross understand the Alien Realms reference as a different division of the 4Td per each due to different psychology. Say, 2 to 3Td of cabin, and 5 to 6 of non-cabin space for the 2 Stateroom pair, and the cabin is shared.
Leaving aside the utter incredulty that the claim that normal humans can't endure ten days in space cooped up in a lot less space than a 2 dT cabin plus some common room space evokes in me, we know for a fact that humans can survive double occupancy for months, since the rules allow is for military and private vessels. I can't think of any other way to prevent commercial vessels from selling double occupancy passage than regulation and enforcement. Given that, some Vargr states might have regulations, but it wouldn't be the same regulations from one state to the next, and a lot of Vargr ships wouldn't operate under any regulations at all.
In fact, that it's constant for Imperials, Aslan, Vargr, Darrians, Vilani, Vegans, Zhodani, Newts, Ael Yael, and even Hivers and Dolphins, but different for Solomani, Droyne, Virushi, Dandies and K'Kree, shows that it's at least partially about needs, not wants.
No, it doesn't. All it shows is that when writing about Imperials, Aslans, Darrians, Vilani, Vegans, Zhodani, Newts, and Ael Yael, the writers either didn't give the issue any thought or deemed it of too little importance to devote word count to.
It's reasonable enough many non-humans would need different amounts of life support and living space. Indeed, the number of non-humans that just happen to require the same amount as humans is rather implausible and most probably another manifestation of the writers not exploring all the ramifications[*].
[*] Please note that this doesn't necessarily reflect badly on the writers; simplification is an essential feature of rules writing.
Solomani are, unlike generic imperials, from a cluster of several overpopulated hive worlds long settled (by the time covered in AM Solomani, 3500 years of space travel, most of it desperately seeking an edge, driven by manifest destiny, and racism - a superiority complex driving tolerance for smaller volumes).
No. Just no. There's no fundamental biological difference between Solomani and any other sub-species of Homo sapiens. If psycological factors can enable Solimani to endure cramped quarters, other psycological factors (like the desire to save money) would enable Imperial, Vilani, Zhodani, Darrians, etc., etc. to endure it too.
And when an adventure conflicts with a rulebook, I side with the rulebook every time.
I know you do. That doesn't prevent me from believing that you're wrong (though not necessarily every time. ) Most of the time you are, though. Except for very, very simple situations, any game rule that describes any feature of a universe as complicated as our own (and the Traveller universe is just that; different from our own in a few ways, but conceptually every bit as complicated) is necessarily a simplification that ignores huge swaths of "reality".
The notion that the rules defines the game universe belongs to board games; it has no place in role-playing games.
Hans