I assume, then, that you've never heard of the Borean languages [0]. Which link the people of southern Asia, northern Europe and South America, culturally, with a common origin around 40-45,000 years ago. The Borean hypothesis is a claim that is made quite seriously, but does not presuppose a universal origin. It is wide reaching, but there are people groups outside of it.
It's an interesting idea, I cannot disprove it. But I don't think it has been proven, either. Even the possible relationship between Uralic, Afroasiatic and Indo-European is not widely accepted yet. Those language families are extensively documented and we can reconstruct their proto-languages convincingly back to somewhat around 10,000 years ago. They look kind of similar in some ways, maybe areal effects? I think to hope for another 10,000 years further back is too much. Borean is a claim about probably further back than even that. The Nostratic and Altaic subsets of the Borean hypothesis, presumably with its proto-language somewhere in Asia around 10,000 years ago, alone is controversial and is not generally accepted.
If we're just going to assume on very loose basis from typological comparison, we might as well assume proto-World, because that's what the sum evidence suggests. But that guess (an idea I do take seriously) is very different from demonstrating their relationship through solid comparative and historical linguistics.
[1] https://en.wikipedia.org/wiki/Den%C3%A9%E2%80%93Yeniseian_la...