How many apple trees are visible in this photo of an Idaho forest? https://www.planetware.com/wpimages/2020/08/idaho-best-natio...

Ceteris paribus, normal trees will always outcompete fruit trees because they don't have to waste any energy on fruit, and use that instead on trunk height, putting fruit trees in their shade and, eventually, starving them to death.

You can, of course, maintain an orchard of fruit trees, manually removing competitor species, but then we're talking about stationary farming, a technology that Plains Indians did not have ten thousand years ago.