That's far more complicated than you'd suspect, at least in the US. There are a litany of policies that criminalize self-sustainment. Granted I suppose one could consume pests without being harangued for poaching, but that doesn't mitigate property laws, and all property is owned if not privately then publicly and in either case most often requires license to be there, whether explicit or implicit. Certainly doing any
reasonable amount of cultivation is seriously complicated by this. So you're legally barred from hunting, barred from cultivation, and you're left with scavenging or gathering and that's highly dependent on a number of factors. Granted the probability of being found out in the depths of the wild are minute, it is nonetheless a serious existential threat. Let's just say we're at the mercy of our captors.
Having addressed the question of legality of rogue individuals... And if an individual exploiting the wild is illegal, so is the group. Humans are social animals. Going it alone at length in the arboreal breast of mother nature would be extraordinarily taxing mentally for most people. That alone is a crucial disincentive, and with the legal disincentive it atomizes people and forces even the highest aspirants to dissolution of the ideal. And that's before the process is even allowed to occur. The impacts of each added person to a group of rogues would compound, and I'd posit exponentially. And with that impact the footprint naturally grows, and with the footprint the risk of detection. At the end of the day the risk assessment points to certain failure.
So the next best thing is urbanized scavenging, not because it's the idyllic means, but because it's the only certainty. If you offered these people license to fuck off, I suspect they would do just that, perhaps not all, but most. I know if I was given license, alongside my friends, to get out of dodge we might just take up that offer. But the whole concept of real liberty, real autonomy, real independence - that's an existential threat to the status quo, to the system, and to the policy makers and corporations that own them, and to the very few of those who pull the strings.