>>18094422
because they didn't. Yamnaya were just the first IE domino. Indo-Aryans are actually in part Corded Ware Culture descended since Sintashta originally came out of Corded Ware but also have fairer farmer ancestry to a significant degree and ancestry from other parts of the Indo-European expansion which we know less about like Andronovo. Both Andronovo and Sintashta came together in BMAC and mixed with the locals before "invading" india and persia.
The picture isn't clear whether they invaded the oxus in the first place. the invasion also isn't as clear when we look at the effects in europe of a verifyable invasion and continued cultural, ritual and technical practices from PIE with a far more clear picture as to what happened genetically on a local level compared to Indo-Aryans where we assess the big picture.
IMO the ruling caste very quickly absorbed into a very willing population and the invasion happened but it was material similar to all other cases where IEs encountered a very urbanised region such as the IVC, the Levant, Mesopotamia etc. Clearly in Persia we see a far richer remnant of IE culture and genetics and that region was also less settled while the mitanni have almost no remnants and would've presented an even more urbanised region than the IVC.
The IVC probably had a cultural structure which received these conquerors fairly easily where in Europe the HG component in EEFs would've presented a larger resistance additional to the actual developments in arms and fortifications of increasingly large and centralised polity like townships leading to increased violence and propensity for extermination and expropriation of the defeated people with women being taken but men being killed where in India IEs conquered but were assimilated but still filled the void left by the IVC collapse culturally and ritually.
