First postulated in the sixteenth century due to people noticing similarities between Latin/Greek and Sanskrit.
Because they didn`t want to see that Sanskrit itself coming from the Slavic. Not to speak of Latin/Greek. Sure, plus all kind of Mediterranean/Asian influences. But, foundations are Slavic.
No, not. Are you running out of medication?
Genetics of Serbians overlap in 60% of Lepenski Vir skeletons. Plus, Lepenski Vir people has tallest skeletons among ancient skeletons. And who are tallest Whites in average? Serbians. Where Serbians live? Their ethnic core is what was Lepenski Vir.
Not to speak of modern scientific clues, discoveries on many fields, linguistic studies, etc.