Company towns.
Capitalism succeeded by technofeudalism.
in a World with a Starport A and low population it's likely the starport IS the world economy.
Indeed.
It's perfectly possible (because it's been done so many times in the history of humaniti) to have a single major employer (THE factory, the Vatican as McPerth cites, the big box store, whatever) that controls the overwhelming majority of the local economy. History is littered with examples of what amount to (in hindsight) Boom & Bust towns where the location "booms" because of something specific to that place (resources, such as gold, petrochemicals, agriculture, unique manufacturing skills, etc.) which then go completely belly up and blow away when the "bust" times come and the music stops, leaving an abandoned ghost town.
In the US there are plenty of stories of boom & bust mining towns throughout the Old West where a valuable resource is found, a town springs up around the exploitation of it, and then when the source of that "wealth" plays out and dries up, the town's economy collapses, people move away and the town just withers away and dies (on the vine, so to speak), becoming an abandoned ghost town.
Not to invoke the politics of
The Pit, but an analogous situation is currently playing out in Brexit Britain right now ... where company towns are having major manufacturers shutter facilities to relocate them to other countries (often the EU, but not always), which devastates the local economies of the towns that supported those industries, sometimes irrevocably. My point here is simply one of the fact that "company towns" dominated by a single industry which in effect "lose the company" are going to suffer disproportionately large economic damages as a result, which can involve the "foreclosing on the future" for the inhabitants who live there ... at which point they need to "up stakes" and move somewhere else to make a living.
A starport that
IS the world economy (as
@McPerth cites) is perfectly possible ... it's been done before, it'll be done again ... but it is not an inherently stable long term option, since it's an
"all eggs in one basket, don't lose the basket" strategy for an entire world's economy. It effectively makes the world economy a "colony" dependent on foreign investment to keep it going, meaning that the world's (starport) economy is utterly dependent upon market forces it cannot hope to control, let alone influence all that effectively, absent a niche role and need for services that are not obtainable elsewhere within a competitive radius.
And on the point of needing "foreign investment" in order to "keep the party going" ... let's take the example
@McPerth provided of Vatican City. If Vatican City were cut off from imports (donations of wealth, supplies, services) and the demand for exports (faith, teaching, records, etc.) completely collapsed ... how long would Vatican City be able to continue operating as it has? If imports+exports fell to zero, would anything change at all? If Vatican City were (somehow) relocated to geosynchronous orbit (for whatever reason) and couldn't import anything ... how long would Vatican City "last" as an ongoing enterprise in its current configuration/state.
My point being that if demand for what Vatican City supplies were to evaporate (effectively), what Vatican City produces would need to change. Likewise, if what Vatican City can bring in were to evaporate (effectively to nothing), it could not continue doing what it has been doing up to this point. Without inputs and outputs, Vatican City would either be abandoned and/or radically repurposed in order to become more self-sufficient.
And it's that self(ish)-sufficiency that is the real sticking point for world economies in scattered star systems around the map of subsectors and sectors of space. By definition, non-industrial worlds are not (yet) self-sustaining in their economic diversification. Most non-industrial worlds are going to be experiencing a variations of the
Resource Curse since non-industrial worlds are typically places for harvesting/resource extraction to be shipped off elsewhere (such as industrial worlds) as raw material inputs for creating Value Added manufactured goods ... which then get shipped out to the non-industrial worlds (at a profitable price) ... and the whole economic colonization proceeds apace. Yes, there is a co-dependent relationship in the structure of the respective world economies, but the trading power dynamic is definitely unequal.
Which means (bringing this back to starports as world economies) that although you can take a stab at an approximation of "labor participation" (in absolute number terms) by using a UWP Population Code (and Trade Codes) like I'm doing here ... being able to definitively nail down how much supply/demand there is going to be for a service such as starship contruction from a type A starport is trickier, since that's going beyond what a UWP is trying to represent.
If the limit is due to workforce, it should affect as much the maximum tonnage of the ships as the number of ships worked on simultaneously...
I'm being modest with my proposal in only trying to limit the maximum tonnage per hull by looking at UWP and Trade Codes, which then becomes a "class design capacity" limit, with low population places more limited in the size of hulls that they can construct (due to a limited quantity of sophonts to oversee and manage the construction project, even if all the "work" is done by robots and automation).
It's the difference been "mom & pop shop" versus megacorporation with unending legions of employees and bottomless resources.
However, I think that in terms of spacecraft production, you need to figure out actually how many starships and spacecraft are manufactured per annum, and I bet, from the Traveller setting, it's a lot less than you think.
If you think in terms of 40 year service lives before being sold off for surplus and/or scrap ... if you build 1 hull per year at a shipyard, after 40 years there will be 40 hulls in circulation from that single construction facility. At that point, the first hull produced will (should) get moved into retirement and replaced, so after that point the number of hulls in circulation from that single construction facility would remain "pegged" at around 40 hulls (give or take) operating out in the wild.
Thus, having shorter construction times is more advantageous (to the shipyard and buyers both) since a single production line can keep more hulls in circulation than just 40 hulls over 40 years.
However, as we ought to know from real world naval construction that the most efficient way to construct tonnage is on a rolling, staggered basis. That's why it's cheaper for Electric Boat to be building two hulls per year (at different phases of completion) rather than just a single hull, finish that one hull before starting to build the next. The construction logistics work out better for utilization and retention of skills and people by building multiple hulls of the same class with offsets in the timing of their construction so as to "keep the party going" and make the work FLOW. That's how you can build 2 submarines at the same time (slightly offset) for less than the cost of building 1 submarine completely before starting work on the next submarine.
It's the difference between Single Production and Volume Production.
So if you've got two production lines, operating out of phase from each other (by let's say, 6 months), you can still be finishing out 2 hulls per year, but the half-year offset in when specialist skills are needed in volume construction of a single class reduces idle down time for skilled workers, improving the utilization efficiency of the workforce you've got available to you.
Which is a long winded way of saying that you can probably get a surprising amount of Tonnage Per Year out of a limited quantity workforce at a type A starport, but expecting them to be able to handle "big jobs" of high tonnage craft may not be reasonable.
10x 200 ton hulls per year ... can do.
1x 2000 ton hull per year ... maybe not ...
