If I remembered my  history, Dena'ina people are part of the Athabaskan people who were one of the last major people to migrate to North America. Many Athabaskans continued to migrate onward. Navajos for example are regarded as southern Athabaskans and it was believed they came to their current location around 1400 hrs or earlier, driving out or destroying the Chacon civilization that existed before them. Places like Chaco, Aztec Ruins or Mesa Verde were built by people who existed prior to the arrival of Athabaskan Navajo people. My guess is, before there was Dena'ina people in the southcentral and interior of Alaska, there were other people living here.  Nothing about this is wrong or strange. Lakota Indians drove out many tribes to claims their lands. Black Hills I read, once belong to the Crows before Lakota claims it as their own forever. If the whites migrated into Alaska in the same way Athabaskans migrated into Alaska, who is to say who the real owners are??