>>50750
In sedentary land there probably is someone who buys horses, cattle, sheep, etc. in bulk. Several someones. In 16-18th centuries (or even later) Hungarian herders drove cattle to Vienna from the Great Plains like that.
In the book the author describes merchant colonies along the caravan road, where some nomads seem to come to seasonally. And he is halfway there to the truth. Steppe people on Earth had settlements (as I stated elsewhere), not everyone had pastoral profession, and there were works to be done which are impossible to do on horseback, most notably creating the tools of war. Where all the arrows came from? A tumen was 10000 warriors, each having arrows not just one quiver. All arrows needed blacksmiths and fletchers. It needed wood, feather, and iron. These needed further people who had to produce the materials. In case of iron, not necessary miners, because lots of the material came from bog iron, but still. There were mines too. Or the wooden structure of the yurt needed carpenters. These aren't just crude sticks tied together any amateur can produce, but wrought staves, and rims. These need proper tools, workbenches, and skill. These are just a couple of jobs from the top of my head. The clothing, blankets were home made for sure by their women while men were on the fields with the livestock.
Along the branches of the silk road large cities could be found (some the size of ancient Rome), some with a mix of population on the periphery of the steppes. But inside the steppes (eg. Sarkel), outsider immigrants were minority.
These cities were the trade centers where the wranglers and "cowboys" and shepherds drove their animals to. Some were sold right to butchers (cities the size of Rome consumed a lot), but sure were many people who wanted them on all fours, since food preserves alive the longest.
Trivia: steppe horses are usually small, "rough" creatures, but in Fergana they reared such breeds which were similar to majestic Arab horses, and were fed with oat fodder.