This reminds me of an earlier posting on another Mailing List I follow where someone asked about another product being turned into Traveller-based rules. That other product and Traveller while sharing a common theme of space, run on two very different histories of space, how travel even functions, and thus the pursuit of relic-based tech in that setting makes sense because space travel itself is not scientific, it's not even using handwavium for tech purposes. It just calls magic another name, and operates by that newly-named magic.
I won't criticize the other game system, but it's very hard to imagine the TU Marc Miller has set out to create, and see a way to play the other game in the TU.
*The other game is obviously Warhammer 40K. Relictech is the sole way many of the human factions travel in that setting. I don't know if there has EVER been a Relictech-based race supposed to exist or proposed. If there is, it might be interesting to read, but I imagine that book was published some time ago, and not in a newer, Traveller-authorized format or edition. (If I am wrong, so be it, I am recent comer to Traveller, so feel free to educate me if I am wrong on this folks)
If you want a Scarcity driven TU, just use the Maritime principle of Chokepoints and Sea Lines of Communication. Travel occurs on regular paths, that of cheapest routes and quickest routes, and scarcity occurs by the constant harassment and inability of powers to fully manage all their Space Lines of Communication and Trade. I would argue that Traveller already exists in this, it just doesn't seem that way because there isn't a galactic war in the current time period. But if you played a campaign during one of the BIG wars, you could definitely carry this out as worlds are invaded, blockaded, and starved. Planets are by some measure self-sufficient, but the natural inclination of Free trade inevitably causes planets to seek cheaper ways of production off-world, meaning food, building materials, military supplies, and general munitions will NOT be produced on one world, but over many in a power, and the point of that power is to secure the safety and consumption of all the trading worlds in League.
In an anarchic setting, without a supreme power over everything, filled with pirates, mercenaries, and megalomaniacs, scarcity is king. It limits operation, consumption, and the imperial spread. From previous discussions I have had, all of this is in play, there just hasn't been the conversion to the idea of specialization in Traveller, because in setting most nations are barely self-sufficient, and each planet is obsessed with self-sufficiency. OTU trade is therefore burgeoning and arguably limited beyond what might be assumed. Feudalism doesn't encourage Free Trade, it encourages Mercantilism.
Scarcity doesn't have to be complicated and can be done outside of Relictech as a necessity. Just draw a map of your local sector, draw the paths that connect the most amount of worlds in a single line, excluding ones of opposition or no allegiance. Those lines are therefore the ones that are going to be the most guarded and the most targeted. When war, skirmish, or piracy occur, it will happen on those well travelled lines. You can draw lines branching from these main lines for detours and subroutes to nearby worlds. Those offer optional lines to get molested and more likely routes to be ignored by the imperial and naval powers. Too many roads, not enough legions.
Choke points are usually formed geographically, but space anomaly and hostile space can create artificial choke points. These are places where regardless of method, all lines must pass through or a majority pass through, for safety, for fuel, for general consumption. Artificial choke points, the most guarded spaces in a line of communication and trade, are likely to be around Gas Giants and Fueling stations. Tolls are likely to be applied on all crossing a choke point, creating tariffs and scarcity through inadequate funding for some companies.
At this point, an actual economist could take over. But that's where I would argue Scarcity from my Political Science and Military Science background.