The tribes could have financed all of their own schools, provided jobs and small business loans, housing mortgages, ad infinitum..
They could have enjoyed a measure of soveriegnty and financial independence that might have fostered a truly different social outcome today..
I almost think this was done to insure their dependence on federal and state aid which of course, fortifies the welfare dependence mindset..
Liberal tools..
I think the reason is far less sinister than that.
People stole the money because nobody was trying to stop them. It grew in scope and scale with every generation of thieves. No political motivation is necessary to act on greed.