"The Sentinelese and Jawari (despite not being hill people) are hunter-gatherers presumably because it allows them to stay independent (enslaved, taxed etc)."
I don't know anything about the Jawari but this just seems like speculation w.r.t the Sentinelese. You're ascribing a single-liftetime conscious decision ("I know civilization, it is bad, so we should all just keep to ourselves in this isolated place and not develop technology") to groups of people who have been living in isolation for centuries, possibly even thousands of years. In the case of the sentinelese, it may not even be a type of cultural evolutionary trait to avoid people so much as a consequence of isolation, that people just don't go there because it's out of the way or they don't know about it. And their hostility to outsiders could have any number of explanations... it could be that they see civilization as a threat to their way of life, but it could also be that they are just scared of people who look different and use seemingly magical tools, or due to some pervasive myth/aspect of their religion.
I don't know anything about the Jawari but this just seems like speculation w.r.t the Sentinelese. You're ascribing a single-liftetime conscious decision ("I know civilization, it is bad, so we should all just keep to ourselves in this isolated place and not develop technology") to groups of people who have been living in isolation for centuries, possibly even thousands of years. In the case of the sentinelese, it may not even be a type of cultural evolutionary trait to avoid people so much as a consequence of isolation, that people just don't go there because it's out of the way or they don't know about it. And their hostility to outsiders could have any number of explanations... it could be that they see civilization as a threat to their way of life, but it could also be that they are just scared of people who look different and use seemingly magical tools, or due to some pervasive myth/aspect of their religion.