It also underestimates the difficulty of finding such pairings to begin with. Most people seem to have trouble finding a 1:1 pairing that is long-term stable an

It also underestimates the difficulty of finding such pairings to begin with. Most people seem to have trouble finding a 1:1 pairing that is long-term stable and desirable. Four adults, as depicted in this story, would presumably require at least twelve long-term stable pairings. That's ... incredibly unlikely. Not impossible, but hardly something I'd expect to become a widespread social trend. There's a reason this traditionally happens in situations of consanginuity: there are strong per-existing bonds that are considered non-negotiable due to existing social structures.