Still common in some places. I don't believe it was ever the norm in all societies, although you imply this. Those practicing it certainly didn't care if it was the "natural order" of things; just that they could accumulate wives because they were more powerful than other men. This left young men without wives, and with little hope for getting a wife anytime soon, and having large numbers of aimless young men about is not good for a society. They tend to break things.
You can see this today in polygamist societies, which tend to produce terrorists as a byproduct.