Are you referring to the entirely debunked theory that human social lives resemble those of wolves in captivity, which is now resonating in incel circles, and that even the original author has been trying to correct for decades?

Unless you meant alpha male as in furries, in which case furries fathering all the children is an interesting point of view.

Bad for genetic diversity.

26% children are already living in single parent households, so we're well on the way :)

Up to a degree.

You would need a group of alpha males to guarantee genetic diversity for future generations, or your little society will start having issues with inbreeding and maybe get killed by a rival tribe.

It's hard to say whether that would yield better results over monogamy after several generations. I wonder if this is an experiment evolution already tried over million of years or if it's a novel approach. Prehistoric men being of similar strength and not having tools would make it hard for an elite to get all women without rebellion. Nowadays, with a population which is mostly unarmed, it would be easier.