One problem is that American Indian is about as useful as saying African for a cultural perspective. The tribes are not of one piece and many really, really didn't get along. Sure, there is a bit of commonality, but it does not extend to the food. The second problem is many of the tribes weren't city dwellers and I've noticed hunter / gathers don't complicate their food enough to get to cuisine that has a place in a restaurant. Plus, much of the way the tribes cooked ended when they were thrown on reservations. The "Indian Taco" is a product of reservations, not of the open plains for example. Also, some of the food ingredients are unacceptable in the modern age.