Yes, this is very interesting - a so-called "primitive" culture doing things in an utterly different way and making it work for them.
For some I can see how they would consider this superior to their own experiences of poly. I do not.
I want my family to be a "chosen" family, rather than one based on genetics - I want to decide who I want in my private space. Most of my family members I would not have wanted there for all sorts of reasons. If I had been forced to stay at home with all my various aunts, cousins, etc, there would have been several homicides out of desperation..
I like that a society can exist thinking so utterly differently, though.