Life is pretty amazing isn't it? I mean, hunting in packs is great, strength in numbers, but also defending in numbers like when a herd closes into itself facing out, then no matter what the pack does it can't really attack. In this case, the hunting pack has to be smart to break up and divide the herd, using brain instead of brawn. Life just has it evenly figured out so that sometimes the prey wins, and sometimes the predator.
Then humans come along and just toss that sh^t out the window, hence no more american buffalo and others.