All true.

 

Not so much, as you need commonly-available AI for that, which in the non-Virus versions of Traveller doesn't exist.

 

I believe that it's possible to have an interstellar economy of scarcity and limited interstellar trade volume at one and the same time, AS LONG AS that trade primarily involves luxury goods. By "luxury" I mean that on the sale end of each trade transit the particular cargo being carried can't be locally produced (or at least can't be locally produced in economical amounts), yet it also isn't essential to life or even to comfort. Cargo such as this is what the top 1% of consumers on the destination world can afford.

Given the glacial annual economic growth rate of the OTU (I think GT:FT puts it at ~0.25%), the aggregate demand for luxury cargo would be relatively restricted and pretty much rock steady along a given route. A situation like RL modern China - where a less-wealthy economy suddenly becomes substantially wealthier in a relatively short time span - would be extremely rare. Since both the number of possible consumers and the scarce supply of any given luxury good is largely fixed, so is the low demand. All that will change on a noticeable scale is *which* luxury good is in current demand. Staying abreast of fashions in high-end consumer goods (at least in the markets that they frequent) thus becomes highly important to interstellar traders. 

BTW, a low-trade OTU still justifies a large Imperium. Such an Imperium exists in order to encourage the development of luxury trade among systems which are largely self-sufficient economically. It does so in order to foster a sense of interstellar community among these worlds. Absent such a sense of interstellar community (limited though it might be), there is no reason for any particular set of close-neighbor worlds to *care* about helping defend any particular other set of close-neighbor worlds from external attack. The Imperial Core Worlds wish to remain safe, yet don't wish to spend the enormous amounts of cash necessary to actively garrison a sprawling frontier. So they finance their protection by selling the Frontier Worlds on the social concept of, "Hey! We're all in this together, gang!"