That is until they die from a simple infection.
Well, I mean, except property rights and the people that will defend them in most of the places in the planet suitable for human habitation.
They tend not to be very wealthy by modern standards. Maybe you could ingratiate yourself to them with them gifts of things that require modern manufacturing infrastructure.
You were born into the tribe, and stayed there your entire life. Also there were no laws on hunting, setting traps, etc.
And the above presumes the existing population would accept you, and it's quite likely they won't.
Deciding to live off the land without special privileges enjoyed by native populations is simply not possible; regular financial transactions between you and society is a requirement, and it's pretty much impossible to raise children without access to modernities and without having the authorities go after you for child abuse.
I love eating wild weeds and berries, but it takes _a lot_ of time to get enough to fill yourself, and it's not a case that people have only eaten stuff like acorns only in times of famine.
This fact by itself made me question a lot of what's in "Sapiens".
Also from what i gather most meat was aquired from trapping, rather than hunting
1. HGs are very skilled, and they build their skills throughout their lives - crucially, starting with childhood and adolescence. I, an adult brought up in a Western civilization, would be totally clueless in a rain forest the same way that those HGs would be totally clueless in our world.
2. HGs live in groups. I would need to find a group of HGs that would accept me, which is highly unlikely because of the language and culture barrier, plus my lack of skills - why would they want to have anything to do with an useless guy in the first place? My CV full of accomplishments does not impress them at all.
Unfortunately, just like transplanting an adult HG into our society most likely ends in them becoming a homeless addict, most likely result for me heading for the jungle is fairly quick death.