How is it any different where you came from? Once you become a teenager the gangs and predatory "adults" start closing in on you to either join/serve or be an outsider they abuse for amusement.
I say this from similar situation as you but I was 16. Much easier since I could legally work in restaurants (which is what I did). I have no idea how you would make it without the ability to work. I'm not saying that I want anyone to go through what I or you did. However it was blindingly clear to me even as a child that staying was equal to dying. I don't see how these people stay in these places having been there myself.
Someone posted the average income at pine ridge is <$4k. You can work for minimum wage for almost a 400% increase in income by leaving.
Mexico. This people needs the wisdom of a Mexican coacher.
Thriving despite racism, lack of money and no friends in town, but with a golden, fully legal document of citizenship granting free pass, and speaking the same language as everybody else?. Yep, Challenge accepted
I'm guessing however that the reservation was put in the most disadvantaged place for doing such traditional activities. A prarie is useless without it's bison. And bison are probably a protected species.
Many would call that poverty or subsistence but many long for it. It may be romanticised but it seems like the essence of life. Heimo Korth (?) In Alaska been doing it for 40 odd years.