So how do we measure equivalency? At the very least, we can compare food quantity, quality and variety, right? And clothing quality and quantity, and housing quality. Right?
Or we can talk about individual satisfaction, and the subjective understanding of comfort. Right?
There's a lot of slipping between real-world concerns and game concerns here, that I think should be disentangled.
Which is not at all how the real world works. Someone trying to survive in the wilderness without survival skills will live at a Wretched level. Have you seen Survivorman? He lives at Wretched or Squalid half the time with proficiency in Survival.
You are confusing being able to survive comfortably and being able to survive without any resources.
Which translates to Comfortable how? You're living in a teepee, hut, shack, lean-to, cave or igloo with essentially no furnishings. You have one or perhaps two sets of rough clothing. Your food source is insecure; some days you eat nothing except perhaps some dried meat. You have zero legal protections, and are at risk from wild animal or monster attack. You probably have lice and/or fleas. Nothing about that says Comfortable to me.
Nor to me, but I am not proficient in Survival. All of these things can be routinely avoided, as you know.
I wouldn't even say that long-established hunter-gatherer tribes live at Comfortable.
I'm not sure what you mean in terms of "long-established" in this case, but (for example) the Northwest Coast ethnographic pattern had large kinship groups, non-nomadic lifestyle, that allowed leisure time for art, social hierarchies, intercultural trade, the development of literature, etc., because they had access to a high-yield, highly predictable resource in the salmon; they were hunter-gatherers.
Are you sure you want to generalize about "long-established hunter-gather tribes"? The cultural expectations we possess in a world with antibiotics, industrialization, etc., have not been shared by humans for most of history.
Exactly. So why does someone with a profession live at Poor? 1 gp/day buys you Modest, not Poor.
And from a game-design aspect, do we want to encourage characters to stay in the woods and away from cities? Why?
Where is the person in the game with a profession that lives poor?
And who is encouraging characters to live in the woods? It's a sidebar, separate from the primary discussion about living in cities.
It appears you are here talking in terms of the game, but neither of these circumstances is clear to me.
I think you are making difficulties for yourself here. Do the rules cover every circumstance? No. Do they give a good benchmark so that most games can get by without worrying about this? yes.
Most people playing adventurers are not concerned with day-to-day non-adventuring salaries: these rules come up from time to time, but they are not what the game is
about. If I roll up a sorcerer, I am not hoping he'll get a steady job in a bank, free from risk and with long-term job stability.