If you poke around a little, you ought to be able to find interviews and essays in which Alexie discusses whether or not one should/ought to leave the reservation. I'm pretty sure you're grossly oversimplifying his position.
Re what happens to "the culture" when people leave the reservation, and the different ways Indians feel about and respond to that, a relevant term you want to keep an eye out for is "urban Indians". The federal government had a relocation program during the '50s and '60s in which they tried to move enormous numbers of Indians off-reservation and into cities; there are a number of organized urban Indian communities that date from then.
(You should probably also keep in mind that quite a few reservations are amalgams of unrelated tribes; there's already been huge cultural and language shifts that come from multiple tribes having to share a single societal structure.)
Re "the expected solution," there's no such thing: not a hive mind. But that should become clear if you keep reading Native authors.
no subject
Re what happens to "the culture" when people leave the reservation, and the different ways Indians feel about and respond to that, a relevant term you want to keep an eye out for is "urban Indians". The federal government had a relocation program during the '50s and '60s in which they tried to move enormous numbers of Indians off-reservation and into cities; there are a number of organized urban Indian communities that date from then.
(You should probably also keep in mind that quite a few reservations are amalgams of unrelated tribes; there's already been huge cultural and language shifts that come from multiple tribes having to share a single societal structure.)
Re "the expected solution," there's no such thing: not a hive mind. But that should become clear if you keep reading Native authors.