Whence sacrifice? Whither sacrifice?

What are the chances that someone sometime in nearly every ancient culture decided that killing animals was a good way to worship their gods? What are the chances that this would be a near-universal practice without any tradition, any traditio /handing-over, of sacrificial rites? Aren’t the facts much better explained if we assume that there was mutual interaction, cross-fertilization, borrowing and mimicry, perhaps an Ur-sacrifice and an Ur-sacrificer?

And then what are the chances that over the course of some centuries animal sacrifice, the near-universal ancient practice, was dramatically reduced, so that it is unheard-of in large parts of our world?