Part of this rests on tribal leadership. Granted they do a much better job than america given their resources, ie primarily the casinos. They have enough for subsidized education and healthcare for tribe members. It's usually not what you'd call great though. As you say, the average tribe citizen sees very little of the profit. Most of it stays in the casinos with the council or whoever's running the board. It's almost like the forces of capital corrupt any power structure they come in contact with.