I was quite amazed to realize that the Golden Horde was way more sophisticated and powerful than most other empires of its time, and still it did not had cities, nor farming, and left really few traces. And that was around 1300, not in prehistoric times.
Also, if you're interested in the relation between farming and civilization but want an adverse position, go read "against the grain". It's also quite mind-opening.
This is a pretty common theme for steppe horsemen, right? You can link this to the fall of probably dozens of empires.
In some sense, this was similar to the Early Medieval Europe, where kings often had itinerant courts rather than permanent capitals.
You could also compare steppe empires to naval empires that were common in the Mediterranean. Both had vast expanses of low-value territory that enabled rapid travel. But the real value was in the surrounding agricultural land and cities.