In the Amazon a lot of the "uncontacted tribes" have been contacted by illegal loggers, miners and in the past rubber harvesters, and have every reason to think we're all a bunch of demons. The ones who still hide out are often the victims of past massacres, and not even the prospect of shoes and plastic cups is enough to overcome their reaction to how they were treated in the past.
If that was true then the longer a tribe remains uncontacted then the more pacific and welcoming it would get. But remote tribes are just as violent than those closer to civilizations; or at least no such correlation have been observed.
there's a pretty big alternative: they survived by integrating with a larger group
(they could either maintain a subculture, or fully integrate and become indistinguishable. either way, they don't necessarily die off when they make contact)
"Integrating" is an interesting choice of words. From what I've seen of the integration, nothing of their genes really survive. Nothing of their culture survives. I don't think it's survival at all. They're absorbed, surely, but in the same way an amoeba absorbs some prey... little pieces of the prey move around doing what those pieces always do, at least for a little while. But eventually those pieces stop moving, and get broken down into ever smaller pieces, until nothing of them remains. And it's just a big amoeba.
Not sure what word is a better choice though. Maybe someone can reply with one.
do you have any citation for the idea that genes rarely survive?
i don't really have any idea what the ratio is. i do know that there are a ton of traceable groups from ancient times today. i don't know that there isn't an even larger number of groups that didn't make it
