I live right next to a reservation and have observed them for years. The reservation system is at fault here. They are either Americans or they are not. This "separate sovereign nation" concept is a complete and utter failure. We give them food stamps, welfare, free medical, you name it, and they continue to fail as a culture. The tribal leaders divvy up the housing according to communistic rules and you are enticed to stay on the reservation with freebies. I worked with a very nice Indian that worked for the phone company and even worked overtime. He lives in utter poverty and his wife recently died from liver failure. They were both alcoholics and their children are in prison. He was fired for DWI, but later got his job back, IMHO because he was an Indian.
Most other people I worked with before retiring live in nice homes, own modern vehicles, own boats, 4 wheelers, and other toys. It is the reservation system that teaches them to suck the gubmint teat and stay under the income standard that would upset the gravy train they are on. So they inter marry within the tribe to qualify for the housing, to qualify for the maximum government money, and generally wallow in self pity for your whole life. This is DESTROYING their culture, not saving it. Soon, they will all be retarded or cripples with all the cousins marrying cousins, and the mental weight of communism will crush their spirits into dust.
It is the reservation system that teaches them to suck the gubmint teat and stay under the income standard that would upset the gravy train they are on. I don't disagree with anything you say, and quite frankly, the reservation system IS working EXACTLY the way that the 19th century U.S. government wanted it to work.