Well of course Star Trek is not realistic. It's entertainment, and it's constrained to be comprehensible to its audience. It does a lot of hand-waving, not just about technology, but about social conditions (does anybody really know how the Federation is organized?) and economics.

Good point about how there must be some economic constraints or they'd build a million Enterprises. Nobody ever accused the writers of consistency.

I was really using Star Trek as a jumping-off place for pondering how radical advances in technology might change the basis of economics. If you posit superabundance of fundamentals like energy or raw materials, how would that affect commerce? You begin to have difficulty even with terminology--what do you mean by "cost" when an input to the system is free; and where would "profit" come from? This hypothetical replication technology is a good example: Direct manufacturing costs are zero for all items that can be replicated, and 100% recycling of the raw feed stocks is implied. Energy might be a cost factor, but then it's implied that they have effectively unlimited access to energy--they bandy about "terawatts" the way we talk about "kilowatts". There are some items that can't be replicated--"latinum" is one and seems to have been invented just so the stories could have a form of currency--and thus any commerce would have to focus on those few items.

The Ferengi are rather amusing characters, intentionally so, of course. Most Star Trek species are avatars for some aspect of human nature, taken to an extreme that becomes a caricature. Ferengi are Republicans.

To say that the don't war among themselves is a matter of definition. They celebrate ritual predation through laissez-faire capitalism. There are indications that their system is so extreme that the penalty for economic failure is literally starvation, so their form of warfare does include death, and certainly suffering. Does it really make a difference if your livelihood, home, possessions, and even life are taken by a alien conqueror rather than an economic competitor of your own species?

I remember now the trading aspect of "Citizen of the Galaxy". I think I recall that when the crews spent money, it was in the form of ship's credits--they could charge purchases and the ship would settle out of its trading accounts. That model seems to predominate in science fiction about traders. CJ Cherryh used it in all her trader stories, and it's been implied in Star Trek too (vague recollection of TNG episodes where the crew on shore leave charges things to the ship). Almost implies shipboard communism, doesn't it?

Aren't you about to leave the country? I'm prepared to have this post hang out here with no reply, but if you do get a chance to reply, the "resurrection" feature will bring it forward. Later....