If you start with the young ones and only breed the docile ones, you’d have cows out of bison in 20-50 years. That would take an actual civilization. One that wasn”t constantly worrying about other less intelligent tribes trying to kill them. Animals don’t domesticate themselves.
Some animals just don't lend themselves to domestication: they never tame even if taken very young, and there aren't any docile ones to selectively breed. People have been trying to domesticate various African antelope and zebras for a long time, with very little success - after many generations, they're just as skittish and ornery as ever.
Even bison have only been semi-domesticated, those that have been in captivity more many generations and selected for docile behavior will still stampede and crash through a fence more often than even the most ornery domestic cattle breeds. I think that the animals that were domesticated were often the ones that were at least somewhat pre-disposed to more docile behavior to begin with.