This is the Muslim secret. Polygamy gives them a ready supply of angry betas, because the potential wives are all taken by older wealthy men.
It doesn't help that this sort of male looks upon women the exact same way they look at a car or a boat: something to have. Even the Columbine killers had the same attitude in their journals ("Can't get girls.") And notice, it's "girls" plural. Like one would not be enough, one must have access to a harem.
This very attitude gives off a scent that scares women away, so frankly, beta males are alone because they deserve to be alone. It's a nasty personality type. No surprise they gravitate to Islam or some other extreme ideology that promises to give them the status (and assets) they think they deserve.
Not just there, but some places in America. There are radical sects of Mormonism that still practice polygamy. One elder in the sect in his 60s or 70s will have 40 or 50 wives from teens to 30s. The younger men are left with virtually no women to marry. Their frustration and bitterness is kept in check with threats of excommunication. Some are even robbed of their wives and children... who again go to the older leaders.
Marriage is between one man and one woman. There is immense wisdom in it being so. Wisdom, that too many have scorned and ridiculed.