Pine Ridge has unemployment of 80-90%, median income of $4000/year, and life expectancy of ~50 years. Many people live without electricity or running water.

I don't know that people who live there say "I'll never amount to anything", I don't think any of us participating in this conversation live there; probably none of us are natives. So we're not talking about what they say about themselves, we're talking about what we say about them.

If not the legacy of expropriation, displacement, and cultural destruction... the usual explanation is that there is just something wrong with these people as people, something wrong, something pathological with their culture. I don't see how that is in any way useful, or somehow more respectful of "agency".

Up until the 70s, children were still being forcibly sent to prison-like boarding schools.

https://archleague.org/article/cheyenne-river-reservation-bo...

I don't think there is anything wrong with Oglala culture. "Social justice" would be restoration of sovreignty, reparations (a massive "marshall plan" level of physical and human infrastructure investment), an apology and general cultural recognition, etc. While a very different situation, New Zealand's reparative policies toward the Maori can provide some models.