This is just something very general and nebulous I wanted to take note of, due in part to the sheer time scale and sweep of the process we are describing here. Something to keep an eye on anyway. I don't necessarily intend this to be a military analysis - though it very well could be - but I'll be using simplified military imagery to stand in for a very complex process - encompassing military, political, social, cultural, economic, ecological, and other kinds of processes - that has been going on for a very long time.
So, the mounted horse archer was one of the great terrors of the ancient world, and by extension, the vast expanse of the steppe. Militarily, the horse archers were an existential threat to the slower armies of the settled societies, which would increasingly enclose themselves in more elaborate and extensive fortresses and walled cities to protect themselves from the strange and terrifying peoples that would suddenly emerge in the frontier lands.
But such resource-intensive constructions typically had to expand, while simultaneously degrading where they settled, encroaching further into the steppe or into other settled societies, so there was an upper limit to their sustainability, which at the same time was set against the growing power of steppe peoples like the Huns and the Mongols, the latter of whom would incorporate specialists like Chinese engineers - and then later, Arab engineers - into their growing ranks to improve their siege capabilities and crack those tougher nuts. And later you had the Turks, coming in hot from the steppe, their DNA mixing with the Persian and Arab lands they conquered, becoming more settled themselves, incorporating engineers into their ranks to eventually develop wonders like that giant cannon that finally punched a hole in the Byzantine shell.
This process of the settling of the nomadic peoples had its mirror image. Because the settled societies were growing in power too. They'd incorporate steppe peoples into their militaries for example, like the Romans did with the Goths, and increasingly adopt nomadic means and technologies like the horse archers and cavalry. And as the nomadic peoples came in from the steppes, with the settled societies rubbing off on them, and then them becoming more settled-like and powerful in turn, they would conquer the settled societies, or grow their own empires from within their decaying bosoms, like the Goths did with the Roman empire, reanimating those empires with the infused nomadic DNA.
And these reanimated empires would arise with the newly acquired genius for movement that the nomadic peoples brought, and become ever more powerful, eventually taking and intermixing those instincts, traditions, techniques, and knowledge, with the deep, resource-intensive, and time-consuming development of firearms and naval and mercantile transportation and navigational technologies, this time going deep into the steppes and largely wiping out the steppe peoples as direct military threats.
And victorious, the increasingly nomadic settled society spread to the ends of the earth, homogenizing wherever it could, replicating itself to sustain and expand itself. But then reaching the ends of its frontiers, it has begun simultaneously cooking itself, polluting itself, and cannibalizing itself. At least in the West, while in the East, a new cooperative, centralizing, and territorializing group of powers - with China at its core - is preparing to dig in, but which through its industrial and technological connectedness with the West, must respond to the West's increasing instability and chaos.
And I suspect now, with the increasing immolation of these stationary and expensive infrastructures and technologies, that we'll eventually see an emergence of a more nomadic mode of settled-ness, as the settled world becomes increasingly unstable in the face of climate change, and we see the growth of a perpetual flow and circulation of refugees, and that the howling plains of the steppes may very well re-assert themselves in another form in the coming century.
