Also helps that they have been interbred with domesticated cattle, and we have tons of tools to do it. Good luck rounding up Bison with just primitive tools.
That's not going to domesticate them. You need to put them into a fenced in area for long periods of time, and control the population. Selecting the ones that are the tamest around humans, and killing the ones that are the most aggressive or uncontrollable.
The indians could not have accomplished this (easily.)