> the very fact that they tend to move around limits how much they can own and carry with them
This is why they used horses/animals to carry their stuff (at least on the Eurasian steppe). If you can carry huge tents with floors risen from the ground etc you can carry some clothes if you want. Just check some pictures of the various tents and how they are constructed. Yes they are portable but by no means small or lightweight.
And as pointed out in the article they wanted really nice clothing as you have to layer and add/remove the layers during the seasons (and even night vs day)
> living far inland, it is harder to reach them using ships
And yet the precursor to the Silk Road (Steppe route) went straight through the Eurasian steppe. Around 10000km of it. That most likely gave them a better access to trade than the average European inland city had.
And even once the Silk Road replaced the Steppe route for the most part the actual horses used to transport stuff on the Silk Road came from the Eurasian Steppe. And the horse nomads on the steppe had horses to trade and the traders on the Silk Road had stuff they wanted in exchange.
Also the steppe nomads did not go around conquering huge amounts of area (see the Mongols and Huns for examples) just because they liked to kill and murder. They did it for mainly the same reason most other large empires did. They wanted the nice stuff (good food, nice clothing, gold/silver, art, etc)