My experience totally differs, most relationships in my circle of acquaintances and my family were formed because of preexisting common interests/hobbies/whatever that are shared by the two eventual partners. ("People who play tennis together", "People who finished college at the same school in the same year", "People frequently attending events of the same fraternity", etc.). Yes, it's not totally random, but the subsets you get are still likely to contain people with very different personalities, attitudes and interests. I admit that this is only from my own observations, and that this is perhaps caused by cultural and environmental differences (I'm from a moderately traditional german family).

But assuming for the moment your model is correct, Lukeprog would still have to smother his attraction to the many woman who aren't polyamourous. So it doesn't really help in that respect, does it?