The trapped individuals are living are living in a location where these sorts of conditions are extreme. Prior to climate change they may have been unthinkable.

People with limited resources don't devote them to mitigating once in a lifetime risks. Their everyday life is constrained: buy a more reliable car vs. save for a child's education. Eat healthier food vs. visit the doctor.

These Native Americans live in a vulnerable location that provides little land-based wealth, isolates them from population centers & thus opportunity, and exposes them to environmental threat.

If you can't see how that impacts their opportunity to "amount to anything," I suggest relocating. Become their neighbors and report back in 10 years whether you think this had any deleterious impact on what your career has amounted to.