Taking us back to Pimane, whilst there aren't going to be many passengers or much freight incoming or outgoing and the only profitable spec trade (using Book 7 rules) will be incoming from Strouden, merchant ships passing through on the main wouldn't be the only ships.
There are two nodes on the X-boat network within J2 - Strouden and Carey. I would expect that there would be a regular courier service between Pimane and both of them run by the IISS to deliver and receive mail.
Given that exports would be very hard-pressed to even break even, the system must be getting income from somewhere. The only potential source that I can see is sale of fuel - maybe they own a couple of small craft to skim fuel from the gas giant for sale to merchants plying the main?
That sounds nice on the surface.....and is very one sided.
Until you also recall that the system's details...
First, the System's Tech Level is a "4" (1860 -1900)....So, they are not repairing and managing their seals/dome/etc... with no Atmo or water
The same can be said of their environmentals
Next, their population: 3...where the Population modifier is a "9", so under ~9,000
So, they most likely don't have much of anything they can do except work the played out mines for resources they can trade.
And, what they can get to trade likely goes to keeping themselves alive....not to trade or enhancement
Added to that, every so often, one of the subsistence miners hits on a chunk of "Holy Crap! This is valuable" and uses it as a ticket out-system for themselves and their family.
According to the OTU, there is only one item of interest which I have made use of IMTU....Rumors that pockets of atmo are hidden in deep crevasses on the world. Claims of these have been made by the locals but in the OTU, the University of Mora have come looking and found nothing.
So, even these visits are limited and no one comes to Pimane to stay.
The fact is, you can't just stamp it with: "this is the standard in the Third Imperium"
You have to look at the details of the location and refer to what would really be happening there?