I'm not saying it's not possible. I'm saying there is a difference between worlds in Traveller, and a starcity not complimenting but existing instead of a starport is not what canon describes. So, there will be a lot of difference between Regina and Capital in 1900. Perhaps tax free zones exist for a certain time period...or for other reasons. They do on Earth today. But that's talking about one planet with fossil fuel ships and planes not interstellar trade using starships with "fusion" reactors. Some ships carry defensive explosives, nuclear weapons, etc. The starport appears to segregate itself from the local community for a reason. The Imperium may not want business build MP Fusion Guns in a starport where the world law level stops at shotguns. Just because you can carry it does not mean they produce it.
If your certain that this is the case for Regina you'll need some supporting evidence. 1248 suggests that Pashus (http://travellermap.com/world.html?sector=Deneb&hex=1432) was converted from a high tech world to a commercial/navy depot. Perhaps that required more cultural acceptance of military starships everywhere with industry creating starcities vs ports & cities. Perhaps this disastrous approach is the real reason for the Civil War since military technology security is easily lost. But it doesn't give niceties or details.
Find manufacturing examples in starports not just TAS, pubs, and warehouses.
The Canonista Theology School, bleh, a game I will gladly bow out of.
I have utterly no interest in defining Regina 1900, other then to note whether the gravesite of the Duke is forgotten cherished or destroyed, and the 4517th Duke's Own exists in some ancient lineage to a present day unit.
I tend to react to absolutist statements, that one about no manufacturing, just don't buy it.
Fossil fueled one planet economies vs. interstellar economies does not prove or disprove, what is always eternal is what provides a payoff, fiscal social and power. I expect 1900 Galaxiad people are the same that way.
And just because most starport game writers may not think in terms of taxation, jobs, development, etc. except in terms of generating smuggling and patron grist for the adventure mill, does not mean a specific institution does not exist or that we have to act First Imperium and because something is not 'in the book' that it cannot exist.