The original question in this thread was: why was PIE culture so successful that it supplanted almost all existing PRE-indo-eurpean languages. Vascon and Etruscan survived (and possibly others), the former evolving into modern Basque, and Etruscan slowly dying out (very likely by the end of first century AD there were no more etruscan speakers)
"pressure from the steppe selected for the unification and scaling-up of agricultural societies into larger groups to more effectively counteract these incursions. This in turn would select for greater size in pastoralist communities, and also other neighbouring agricultural groups who were now relatively smaller and at a competitive disadvantage with their neighbours. This effect would be amplified by the diffusion of such military technology from the steppe"
From this awesome modeling paper https://www.nature.com/articles/s41599-020-0516-2
How about Finno-Ugric? While the Hungarians only arrived about 1000 years ago, the ancestors of the Finns, Sami and related groups have lived in North-East Europe possibly since the last Ice Age (although this is much disputed, and it could be they adopted Proto-Finnic from some later migration).
However, as the article mentions, it's unwise to assume there is a 100% correlation between genetic markers and culture/language. The Baltic Sea region has been a trade hub since before the the first indo-european migrations into the area, and some genetic mixing must have been unavoidable.