The history of the great steppe stretching from mongolian plateau all the way to western poland is basically a history of mongolians (the Asian people) pushing westwards, while the Causasians, in particular the Indo-Europeans, were pushed westerwards or even exterminated.
The question is, how did this happen? Why did it turn out this way?
The indo-europeans had an upper hand at first. They mastered horse riding and even horse archery first, chariorts, bronze weapons etc. and expanded in all directions, the east-most expanded to East Turkestan (modern day north-west China). The indo europeans were toally dominate in Central Asia and the great steppe bascially belonged to the indo europeans except many some small parts of mongolia.
However, gradually around age of the late Roman empire, the power shifted. The Huns came from the steppe and basically caused so much destruction they shifted the Germanic people westwards.
However Asiatic people by that time was still minority in terms of population count, as the Huns, Magyars, Avars, Bulgars, all Asian people settled down then assimilated into local indo-european (so-called white) people.
Then, the mongolians came, they were the paradigm shift. They totally destructed Central Asia and made it de-indo-europeaned and made the population very asian (just look like modern day typical kyzerstan people compared to people from Afghinisatan, one is asian, another is still caucasian).
It wasn’t until the Russian conquest that the steppe was back into indo-european control again.
So bascially, how did the Asiatic people gain upper hand in terms of domination over the Eurasian Steppe? Horse riding and archery was invented by Schytians and Samartian who were indo-europeans, yet these indo-euopeans bascially lost the battle over the steppe until the gun-powder age.
Why? What are the reasons?