It hasn't worked perfectly though, as the vaste majority of American bisons (all but 4 herds in fact) aren't true bisons but have cattle genes due to hybridation.
Private cattle ranches could never have competed with 30 million bison owned by nature, free for anyone to take.
Just because the population was wild then wouldn't have precluded ranching bison, or even cows.
Buffalo will run off a cliff in the hundreds because those in the back can’t see what’s in the front.
https://en.wikipedia.org/wiki/Buffalo_jump
https://en.wikipedia.org/wiki/Ha-ha
There are second hand accounts from indigenous people, excavated bone sites with tools and spear tips, but reportedly no first hand recorded observations from Europeans of buffalo running off cliffs.
Also, not voluntarily pushing the beasts to your fences is going to help a bit, since buffaloes don't run to cliff on their own…