Why do you find all people biased that doesn't agree with your own theory?
Seleucid was himself of Macedonian descent and behind the phalanx was neither Philip or Alexander the one that mastered this formation but Ptolemaics in the battle of Panium,the Successor Kingdoms of Macedon's empire they tried expanding upon the design, creating pikes as long as 6.75 m (22.1 ft), but all of these ideas were eventually abandoned in favor of the battle-tried Philippine-Alexandrian sarissa,they were both using them,Seleucids were not something else neither from different military "school" he of course knew how to fight and what tactics he should use btw against their buddies Ptolemaics but as you can see that this Phalanx made their way to India the Persian chariots were utterly defeated by them over and over again,the cavalry was important thing too but not much more then the Peltast i can mention the Thracian Agrianes and their great contribution to Alexander victories,they were javelin throwers and an elite unit of Alexander the Great's light infantry,they were protecting the Phalanx.It is military formation in which all of them have contributio,all historians give them credit that they contributed the most for Macedonian victories but you deny this?somehow you think that the cavalry is superior to anything else.
Don't understand you what cataphract has to do with early Indo-Europeans in Europe?
The reliance on cavalry as a means of warfare in general lies with the ancient inhabitants of the Central Asian steppes in early antiquity, who were one of the first peoples to domesticate the horse and pioneered the development of the chariot. Most of these nomadic tribes and wandering pastoralists circa 2000 BC were largely Bronze-Age, Iranian populations who migrated from the steppes of Central Asia into the Iranian Plateau and Greater Iran from around 1000 BC to 800 BC. Two of these tribes are attested based upon archaeological evidence: the Mitanni and the Kassites. Although evidence is scant, they are believed to have raised and bred horses for specific purposes, as is evidenced by the large archaeological record of their use of the chariot and several treatises on the training of chariot horses.The one founding prerequisite towards the development of cataphract cavalry in the Ancient Near East, apart from advanced metalworking techniques and the necessary grazing pastures for raising horses, was the evolution of selective breeding and animal husbandry. Cataphract cavalry needed immensely strong and endurant horses, and without selectively breeding horses for muscular strength and hardiness, they would have surely not been able to bear the immense loads of armor and a rider during the strain of battle.The Near East is generally believed to have been the focal point for where this first occurred.
If there was much of horseman culture in what is now Poland why would you adopt a Hussar cavalry introduced by Serbian and Hungarian merchants?however they contributed for the decisive victory in the battle of Vienna against Ottomans.
Early "Proto-Cossack" groups are generally reported to have come into existence within the present-day Ukraine in the mid-13th century as the influence of Cumans grew weak though some have ascribed their origins to as early as the tenth century.Some historians suggest that the Cossack people were of mixed ethnic origins, descending from Russians, Ukrainians, Moldavians, Poles, Turks, Tatars, and others who settled or passed through the vast Steppe.However some Turkologists argue that Cossacks are descendants of native Cumans of Ukraine, who lived there long ago before the Mongol invasion.
I will again however for this Nomadic warfare give credit to Iranic and Turkic speaking people of the steppe who knows if there was others among them? Later we have the Cumans.
They had always contact with South East Europe firstly with Thracians then other groups of people "meeting" in present Ukraine Black sea region somewhere.
In my opinion Nomadic warfare is good for raiding or plunder as they raid and retreat but for something durable you need infantry as well more mixed military formation,while all of them are important,i don't know why we should make so much big deal of cavalry?
All humans bear the mark of Cain, although perhaps it's fainter in some than in others.