Nah, the vast majority of groups of humans we think of as extinct (I mean in the historical era, say avars, thracians, cumans, vandals, etc. etc.) not in prehis

Nah, the vast majority of groups of humans we think of as extinct (I mean in the historical era, say avars, thracians, cumans, vandals, etc. etc.) not in prehistory (of prehistoric groups hardly anything is known) blended into later populations and did not go extinct by the way of each member being killed. The further we go back into the past, such mass killing would be less possible technologically not more so.